A lo-fi track i made mostly in Korg DS-10 using my Nintendo DS, then beefed up a bit in Renoise. 
I’ ve been considering getting an game boy just or the ds synth .
How is the newer dsn 12 ?
Only thing holding me back at the moment is the way you have to puchase these things , paying with nintendo credits on their site , kind of puts me off .
I think there is also now a DS10 for iPad / iPhone available:
https://itunes.apple.com/de/app/korg-ids-10/id999702563?mt=8
Ah, DSN-12 looks sweet, too bad i only have a DSi XL.
I haven’t really purchased the DS-10 because i can’t find it on a cartridge and the web shop thingy does not work because i use a flash cartridge to run homebrew stuff and it doesn’t like updates and shit.
It’s pretty sweet, i use it for NitroTracker. drawing/animation apps and playing old Dos games that used the same engine as Day Of The Tentacle, Sam & Max. Monkey Island and so on. I think it even runs Full Throttle pretty good. Lot’s of neat stuff out there, if you get a DS you should look into if there is any available flash cards for it, makes it so much more useful.
NitroTracker is a tracker that saves in mod format so you can later import it in Renoise, great for scetching ideas when traveling. It is homebrew so you must have a flash card to run it.
You get to use the stylus with the DS models and that is a great advantage over the older gameboy consoles. With a DS and a flash cartridge you can run a gameboy emulator on it anyway.