Blaz4me wrote: Meaning the tutor hasn't and can't touch every single aspect of the MPC.
I'm actually sitting here at my laptop writing the last couple of chapters to my MPC2000XL Ebook which I'm hoping will answer most questions - including the original question in this post
Looping is definitely the way to approach extending a musical sample because it's the most effective way to increase length without affecting the pitch. Timestretching isn't the great as it starts screwing with the sound after around 10%.
I've actually found looping on the MPC to be a lot easier with practice - it'll never be as easy as using Soundforge, but I can loop most notes on my MPC within 5 minutes these days. There will be a detailed description of the MPC looping proceedures in the Ebook.