Have you read this faq (and other info): http://www.pvv.ntnu.no/~knutinh/tritonhardware/index.htm
Expansion slots:
triton, pro, pro-x:2xpcm, 2xram, scsi, moss
triton rack: 8xpcm, 3xram, scsi, moss, digital out, mLan
Karma: 2xpcm, moss
Internal hd:
none that I have heard of. The drive adds no features that cant be accessed from an external scsi hd.
External hds, cdrom and optical media are supported. essentially, the triton cannot take advantage of fast drives or interfaces. See my site for compatibility list.
best regards
Knut inge