Jay, I agree that would be the best option, but I really wanted something that charges via USB and doesn't consume too much battery power, as I want to be able to charge off powerbanks when I go travelling. Also, I've got a 50W solar panel kit (with USB ports) lying around that I want to actually use for... something.
After further investigation, it seems my options are as follows:
Suck it up and use Sunvox (great program, horrible UI.)
Dig deep in my pockets, get an Ipad, and use Vividtracker.
Get an old PDA and run Milky (though I've read FX commands aren't supported in the portable version.)
Get an Android tablet, a portable keyboard, and then I SHOULD(?) be able to run Bassoon Tracker or any DOS\Win9x tracker via emulation.
Vividtracker looks really good, actually: 8CH PT clone, and with the pattern2sample function. But I can't justify the cost of an Ipad, especially knowing that I will end up breaking it within a year (like most phones I've had.)
So the last option looks like the best for my needs. Though I reckon you'd need quite a beefy device to run an emulated tracker on Android; has anyone got any info on this?