Maybe you have a look at this post
http://www.mpc-forums.com/viewtopic.php?p=909043#p909043. I'd say this goes beyond beat making. Maybe I'm not that blessed with mics, turntables and routing cables as you are, but I never said, that I can't use that tool for making music. First of all I misplaced this topic and it should be under "What can your MPC 5000 do". Secondly I tried to express, that the MPC is (at least) a sampler, so you could (if you don't see any other options) sample a sound and re-use it. So the MPC is capable of doing every (hearable) sound like Britney Spears can sing (move lips to playback) in every octave, speed and language.
The most interesting part of your post was:
I also have a turntable connected to the MPC, routed through my mixer, and back into my MPC so I can pull samples easily.
. My MPC has only one pair of input jacks, I can't plug a stereo turntable with it's full channel bandwith into my MPC, route it to some mixer and feed it back into the MPC - lucky man.
Don't just write some sort of bashing posts, you don't need to recommend to read the manual, as I already did (for example have a look at the Bug Parade, where I talked about the missing parameters of some EFX). But to get you really going: That synth idea was really funny, I couldn't resist to move parts of my face upwards as if I'd be trying to smile.
So where to go from here: show off some of your MPC skillz and go beyond beat making. I'll honestly call myself unworthy to post again here.