hiphop to a degree, is a different set of skills than mixing house, yeah the fundamentals are the same but the details are really different.. house music generally consists of the same 4/4 bass hit and should be slowly blended between intros & outros, creating a smooth blend.. hiphop requires quick mixing & cuts.. you generally need alot larger music collection to mix hiphop because as the OP quoted, songs vary ALOT in BPM.. so for every track to be beatmatchable, you need alot of tracks progressing in bpm to be able to properly sustain a decent mix set.. remember, your mixing, not just dropping tracks and doing fades.. the rules of beatmatching still apply when DJing hiphop..