There are some ideas that come to mind that could make it happen - to a degree...
- Use the Apple Logo as a glass panel, the rest of the back of the iPad can be aluminum or whatever to keep it
- It would help to use magsafe to help "click" into place with compatible chargers.
- Charging would be limited in speed/watts in order to better control the heat. Maybe a dynamic charging rate based on thermal readings (or whatever tech)
Likely, this wouldn't be the most ideal way to charge as USB-C could do it much more efficiently. However, it would be nice to be able to get some charge using wireless. My kids have tried to put the iPad mini on the wireless charger and couldn't believe it didn't work. We would leave it on the charger all night, so a slow charging rate would not be a problem for that iPad. Wireless charging for iPad is not a big deal to me. It would just be nice sometimes.