I’m going to make a suggestion that I may actually try out myself…
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Assioma pedals use Xpedo Thrust NXL pedal bodies. I’m not sure if it is standard or slightly altered to accommodate the thin part of the pod that butts up to the body.
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All Xpedo pedals use exactly the same bearings in a 1 outboard, 2 inboard arrangement with a nut screwed onto the end of the spindle to keep everything in place. Assioma’s bearing kit looks to be the same.
I can’t be sure that the spindles will be compatible but I may well splash out on a set of M-Force spindles (£20) to test out the theory. If it works the Xpedo SPD compatible pedal bodies should fit on the Assioma spindles and hey, presto, a pair of SPD power meter pedals.
It’s a shame that the pod sticks out beyond the end of the cranks which makes them vulnerable for proper mountain biking but they could be good for gravel use.
Not sure that the clearance to the pod will be like or whether they’d still be accurate. Who knows, but it may be worth a test.
Mike
Gravel and simple single-track here in the Netherlands is exactly my idea. And winter riding with spd pedals.
I’m really, really interested in the results. If you need any help one way or the other, tell me.
Keep us posted about the results!
That idea is a lot more practical than 3D-printing a pedal body - the OP seems to have forgotten all the clip-on mechanism parts. You’d need to get those from another pedal body, and do quite some machining on the printed parts both to make the bearings fit and to allow installation of the clip-on mechanism. It is possible however that inboard bearing placement has been altered from the original Xpedo to give more room to the strain gauges. You’d have to take an Assioma apart and compare it to an Xpedo. For someone who owns Assiomas, getting a used pair of Xpedos would make this a low-cost experiment. Maybe it fits, maybe it fits with some machining, or maybe you get a pair of pedals you did not need.
Is it possible to just learn from Garmin Vector experience about using a cartridge kit to convert Look to Shimano petal?
If the inner diameter of selected Shimano pedal is larger than Assima pedal, then it is possible to handmade an “adapter or tube” by CNC for either metals or engineering plastics, also CFRP-made is considerable.
Personal use, no license violated issue.
There’s a pretty big difference mechanically between how Garmin vs Favero are built. Favero uses an inboard pod, pushing the pedal out and giving room for the electronics and the strain gauges, but allowing the use of what appears to be a fairly stock pedal body. Garmin has an overlapp between the pedal body and the strain gauges, forcing relocation of bearings compared with a “standard” pedal - and thus the pedal body is not the same as any other pedal on the market.
Thus the stock-to-stock pedal body swap idea may work with Assiomas, but is not applicable to Garmin Vectors.
Well I may have done it! Last night I finished installing the pedal body from an xpedo spd pedal (m-force 4) to the spindle of the assiamo duo. Everything fit nicely and no modifications were needed…well I did have to trim part of my shoe (just the rubber on the crank side) so that my MTB shoe would clear the assioma housing.
My q-factor is now 53mm which is 1mm off the original assioma q-factor of 54mm but I my measuring method was crude and it could very well be 54mm. I took it out for a short ride and everything worked (watts and rpm). No play in the pedal whatsoever and I could clip in and out without interfering with the assioma housing. Now I should be able to swap the assioma spindle from MTB to road bike and just switch the pedal bodies. Thanks for the idea. I will update if I run into any issues.
p.s. I should note that I only do gravel and light trail riding on my MTB. Just wanted to avoid stepping off with a road shoe. Would not consider this for true MTB riding where the assioama would be susceptible to damage from the terrain.
CHEERS!
Killer!
One thing I’d consider is crank end caps, to try and protect the pedal base against ground strikes. The pods look to be flush with or even further out than the crank arm.
That’s awesome! If you have a trainer with a built in power meter it would be interesting to see how the power correlates. …or we could try to convince @GPLama to give this a shot and run it through his lab tests.
Or even better, convince Favero to make this a production version.
That’s great. As you say, maybe not a fully fledged MTB pedal but more than useful for gravel.
Thanks for trying this.
Mike
This is seriously cool. It would be interesting to find out how sturdy they are (and also how easy it is to replace the bearings). I’d love a set of pedal power meters for my 'cross bike.
And I’ve just seen that SRM have an MTB power meter pedal coming out at the end of the year. Sounds interesting, if expensive (1000EUR). If the Shimano patent on SPD is now over, maybe we’ll see Favero produce one of these sooner rather than later too? 
Ti is relatively easy to ALM. Problem is as mentioned the feature accuracy in final form is probably not good enough. Also the material properties of ALM material can be wildly different from traditionally machined stuff. We have decades of metallurgical knowledge on that stuff. We are only digging into that with ALM materials now. Sure you can go for it yourself and test the hell out of it before use. Such an approach is not feasible for any mass produced product. Never mind the warranty issues for using a novel process with limited material characterization.
I have a wahoo kickr and plan to test it later today. Will update with results
Keep us posted!!
SPD compatible power pedals are coming. SRM debuts first ever MTB power meter pedals | Eurobike 2019 - BikeRadar
I’ve read elsewhere that the SPD patent has, is about to (or maybe has just recently) expire, and that there may be more SPD power pedals options in the near future,
Nice. It’s now clear why Assioma MTB pedals are not so easy to convert.
okay, here it is. An 11 mile ride in zwift (35 minutes) some flat, a little climbing and some short sprints (very short)
See image below.
You wont believe this but the average watts for entire ride from the Assioma modification and the wahoo kickr were exactly the same!!!
For my purposes, this modification is within tolerances 
Dude, thats a legendary hack!!