I'd like to order some twelve inch cutting in an attempt to grow some cactus as all my from seed attempts have failed.

Anyone know of an eBay seller that has good bridgrssii or Peruvians cuttings

cactusarizona.com

You might want to search them on ebay, then go to chat and enter the link, asking for opinions. Lots of Cactus enthusiasts in chat. Also, cuttings are plentiful, and I've ordered lots of them but rooted cacti establish far more quickly.

this^^

and check the seed/plant supplier section. There are some good ones in there.