I am surprised no one has pointed this out yet. What you are asking IS POSSIBLE with the MPC 1000. Just hop on to JJos2. You use the Extra Audio features, which is Real Time Timestretch and Real Time Pitch Shift. Only downside, and it is a huge issue with me, is you can not record this in anyway with the mpc I am not sure if this is a hardware limitation or something jj can implement in the near(fingers crossed) future. Hopefully this helps you some!
BTW- I don't use jjos2 anymore I am on 2xl and timestretching in the trim menu is super quick all you do is make the sample a certain amount of bars, type that into the timestretch tempo menu and the time signature hit manual, then hit the new bpm you want and you are done, should take no longer than 20 seconds at MOST. I see you were saying pitch shifting and timestretching for you on the mp takes almost an hour for a sample?!?!?!?! How is this so? Maybe you need to watch some tutorials online or check out the tutorial that mpc-tutor does. I am sure once you get down a comfortable workflow with the timestretching on the mp you will notice it is not so bad.
In reality though , the timestretch algorithm in the mp is not very good compared to most soft samplers. I find timestretching is good in the mpc to get the idea down on the spot but if it is more than 15 or 20 bpm , when tracking out I re stretch the sample with kontakt because it IS SO much better, but like I said the mp is is great for getting those ideas down on the fly. Anyways like I said before I hope I was of some help to you. Take care.
-Tom