.xi (extended instrument) support?
I don't have my Deluge yet, so forgive me if this is already implemented and consider this a curious question instead of a suggestion, but...
The .xi format was created, I think, for FastTracker, and is supported by MilkyTracker, OpenMPT and other trackers. If I have my facts straight, it's a single layer (most likely wav-based) multisample format, conceptually similar to soundfont but simpler. A few years back, I had a handheld device with Milkytracker on it and I collected a bunch of these files and I found them to be pretty neat. Some where chromatic, some were drum kits. A lot of '80s-esque sounds for some reason.
Watching videos on the Deluge's multisample functionality reminded me of these instruments. Not because it's a 1:1 thing necessarily, but the apparent simplicity of the .xi format made me think it would be really practical if the Deluge could import such files, since you can easily make them with free software on a computer (Windows, OSX, Linux...you could probably make them on a cellphone too, but it might be a bit more frustrating), and they're practical for storing and transferring, being single files rather than folders, plus there are a bunch of free ones already floating around the Internet, making it really easy to build a starter library.
I'm not a programmer, but I assume this would be easier to implement than for example soundfont support (although obviously if it happens to turn out soundfont support is easy, consider that a suggestion as well, I guess, since there's a ton of those around also).
Just a thought that hit me. It might be impossible for reasons I don't know about, so you know, feel free to ignore it, but on the surface it seems like the peg and the hole are pretty much the same shape and it might give the multisample loading process a bit of a shortcut.