I can't remember seeing any shell dwellers here, or at least in recent times in terms of Lamprologus sp.
Every now and then some 'Alto's' are around but not so much the dwarf varirties.
Juli's, Lelupi, brichardi, pulcher etc seem readily available but it would be awesome to get in some shell spawners.
I agree about the apisto's, cockatoo's, agazizii's, etc are cool and would be a pretty nice alternative.