Do you remember those brightly colored new ones I picked up last year? They ended up being new varieties D. Perfect Orange, D. Pink Ribbons and D. Carmen Lucia. I took cuttings and have them blooming in the basement right now. They bloom constantly. I'm not too sure they will be reliably hardy here.
I've got others, but I don't have D. Davyi or Kelaidis yet, but I probably will by the end of this summer since they are available locally. I like Delosperma.