Studying the Pyraminx Crystal, I am assuming it is technically identical to the megaminx. Would this be right?

I've studied this puzzle, too, and I'm convinced you cannot make one from a Megaminx. When you rotate the face of a Megaminx, 10 pieces move. When you rotate a Pyraminx Crystal, 15 pieces move. You need a different internal mechanism!

It is Deep cut, the pyraminx crystal, that is. Theres a pic on sandy's site

Yes, you're right. But I believe it can be made from an altered megaminx core.

That's a later project. I'm still thinking it through.

Good luck on that, by the way how goes the 6x6x6

It must be possible to mod a megaminx to make it. This is how I thought about doing it.

Sand down megaminx to a sphere, should make for a more stable puzzle than simply using the kernel. (Could stop here and paint a globe on it for an interesting puzzle!)

Build up the pieces with sheet material & milliput. Corners should be simple, edges will need a key that runs under the corners. Maybe cast from these pieces if they are good enough.

Should do it!

Lots of work

Max