Ebay is a great place to find odd seeds but I would go a little further than April and say don't buy from anyone outside the US. And, even if they are based in the US, if they are selling cactus seed and used tires, t-shirts, etc. - don't buy from them. Make sure they actually have a cactus nursery. Otherwise, you will be buying (grass)seeds that the vendor bought from China and repackaged.
Keith, those variegated ones are gorgeous!
Daisy