Does an adapter for my 12x142mm thru axle frame exist to use QR hubs? I'm specifically looking to adapt the rear thru axle (12x142mm) to fit onto a standard QR hub/axle on my direct drive trainer. Unfortunately, my trainer is too old (original Elite Turbo Muin), so it cannot be converted using a converter like Wahoo and Tacx have. I think I have to add things to the bike side if I want to make it work without having to buy a new trainer. I feel like it should be possible to have a piece fit in to the drive side of the thru axle to let a QR skewer screw in and another piece on the non-drive side to fill in the gap and sit on the axle itself. I would then send the skewer through the whole thing. 

Is this possible? If not, why?
To convert your frame to QR you would need to replace your dropouts, which is problematic as they are either bonded or welded in place on the frame. This is basically a no go.

A much easier solution however is to replace your thru axle itself with another thru axle that gives ends that are compatible with older trainers.  These exist and are reasonably affordable (well affordable when compared to major frame reconstruction or or a frame swap).

A couple examples are pictured below:





Some creative internet searches should bring you to where these are available for purchase.  As Stack Exchange does not make product recommendations I have avoided direct links to the products.