Anyone know how the Mental Block works?
What kind of mechanism is it built on?
Does anyone actually own or have played with one of these things?
And finally, is there any way to make one out of existing puzzles, even if it doesn't look as good as the real one?

If you're not sure what a Mental Block is go here:
http://www.puzzle-shop.de/mental-block.html

: Anyone know how the Mental Block works?

Sure do.

: What kind of mechanism is it built on?

Believe it or not, it's no more than a repackaged Skewb, where the centres and corners on the block are the centres of the Skewb, and the edges on the block are corners on the Skewb. In spite of the real mind screwing shapes it can be contorted into (see the pictures at the Puzzle Shop), it can be solved in exactly the same way. L8r.

Is it solved exactly like a regular skewb, or does face orientation matter?

The face orentation does matter for the corner cubes. The center ones don't matter. It seems like you could make one by adding stuff to a skewb. Enjoy!
Michael