All Cubilas.com expansions are compatible with modern MPCs in standalone running on firmware 2.x and 3.x and the MPC Software
$0+
Here's three beat construction kits I created by recording sounds from the Roland SoundCanvas SK-88 PRO into a Korg CR-4 cassette multitrack and resampling that tape into the MPC. These include separate bass, chord/lead and drum instruments.
Just something to play around with!