The hiphop instrumentals I like the most are the ones that RJD2 does. Especially this one he did for MF Doom:
http://www.youtube.com/watch?v=dR8r1ULhVEMHe also does albums kind of like Alias does with just instrumentals that are not really built to rap over. Deadringer is a pretty good one of those but you probably already listened to it.
Actually, I mentioned MF Doom before, he sometimes makes instrumentals for himself. He releases them on albums called 'Special Herbs' under the name Metal Fingers. There's like ten of these or something. Some of the instrumentals on them are awesome and others are boring.
Also EL-P put out the instrumentals he did for Cannibal Ox's The Cold Vein. He is one thousand million times better as producing than he is at rapping/writing and Cannibal Ox rules so I highly recommend looking into that if you didn't already.
Hope some of this was what you were looking for.