1- eBay (eBay UK have more than eBay US)
2- Tangle 1, Tangle 2, Tangle 3, Tangle 4, (25 tiles each.)
(The new one, has 9 double-sided plastic tiles check Hessport @ Rubik.com)
3-No one has yet proven that a 10 x 10 can be made !
(I read several old cube lovers digest, and no one had found a solution....yet)
4-I have the 4 sets, but I am not selling them, sorry.
5-I have a solution for one of them (Tangle 2), oneday if I ever i have more spare time, I'll play with them.)
6- Sold by Matchbox
For some odd reason, #3 is harder to come upon.
Good luck hunting down the 4 tangles, and trying to find a solution to the 10x10.