at least one BF member has seen the peacock-pheasant
http://www.birdforum.net/showthread.php?t=191580&highlight=peacock-pheasant
although under Larry's rules it could be a good bird to stick on the not seen list. I think it is relatively easier to see in kalimantan than in sabah which explains why it's not seen that often.
spectacled flowerpecker; i'm sure no-one on BF will have seen it is but it's undescribed (rules Larry?).
hose's broadbill is easy enough that someone will have seen it i'm sure - probably not worth adding
good shout on dulit partidge though, although i'm not sure if it is allowable taxonomically (not a universal split)
thinking of bornean endemics (and going off on a tangent) javan green magpie might be a good one also?
james