Wetspotcx on aquabid is where I got mine. They actually have them still for sale as the spot faced pikes in the South American Cichlid section.
http://www.monsterfishkeepers.com/forums/showthread.php?520809-Whooooose-that-Laaaaady!-!
He gives some photos of his lents there.
And currently I dont know of any vendors who have them. Rapps doesnt have any on his stock list, there's none of Aquabid, and digging through the vendor section for this is a little to much work to do while at work
They are beautiful though, and I am really glad I got the 4 I have. They are somewhat common, and I got the 4 I have for $40 a piece from Aquabid.
Isde02, AquascapeOnline has lenticulata, supposedly from the rio negro.