How much "empty space" is inside of the housing?

Hey iFixers!

Bizarre question, but hear me out.

I'm into modifying stuff. It's fun. I want a wireless qi charging phone. But I like iPhones. And apple doesn't do induction charging.

Qi seems to be the standard for wireless charging these days. And the technology is really coming along - the coils to accept the charge are absurdly thin (1.2mm) and cheap.

So - Would it be possible to cram one of these inside of the iPhone?

I would attempt the mod first with a 1G iPad, as I know there is a fair amount of extra room in there, but I'm not sure if the signals could permeate through the aluminum casing.

So I look to you - how feasible is this? Am I insane? Probably.

Thanks for reading. I look forward to your responses.

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If this is the wrong place to post this, please let me know and I will remove my post ASAP! Thanks again.