If you are into trackers (most efficient way to sequence songs IMHO) you might want to check out LGPT (piggy). It is a sample based 8 track sequencer that also has midi sequencing capabilities if you use either the windows (no thanks) or the gp2x (awesome!) versions. For the awesome version you need a gp2x running lgpt and a piggy to midi interface. GP2X’s (either f100 or f200) turn up on ebay frequently. The last one I was watching went for 50 bucks. The interface is 65 built or 28 for DIY board and chip.
I tested out my set up last week with shruti and it works great. I was able to sequence notes and CC messages, and sync shruti and my micron (wasn’t able to do this before). I plan on using 3 tracks for samples, 3 tracks for micron sequencing and 1 track for shruti and 1 track for shruthi, but if you want to go all mutable instruments you could control 8 of them!
I didn’t test every single one of the Shruti CC’s, but all the ones I did use worked perfectly. I’m not sure how the polychaining will fit into the picture, but the arp/sequencer midi clock sync’d then sequenced by lgpt will be great.