I immediately had to know what I was looking at. I recently nearly pulled the trigger on the Sony PSP to achieve the same ends.
My house is filled with Nintendo handhelds, no naturally I'd much rather use the devices I own and get one of those set up with some Commodore goodness that go down a whole new hardware path.
I've been beta testing the new Doublesided Games RPG-lite game Hired Sword 2 (much more on this very soon), and having the game on a mobile device would really allow a lot more opportunities to keep hackin' and slashin' at bugs. One of the other members on the team does this for their testing environment, and it filled me with envy. It's very cool.
Anyway, in order for this to work, you have to acquire a small device that is not hard to find but can be a little bit spendy called the SuperCard DSTwo. Rydian via gbatemp.net:
It's main selling feature is that it can be inserted in a DS (or NDS or GBA, and now new versions even support the 3DS) and can run literally thousands of DS, GBA, SNES cartridge ROMs. It has all kinds of plugins for it.It is a device that has the same look and shape as a DS game cart (and goes into the same slot), but it's unofficial, and it has a MicroSD slot to store your ROMs and homebrew.
Someone has even created a C64 emulator for it that I've fired up on it as well. I need to see if I can better understand how to actually install, mount and run disks and d64 files. In the first few minutes of use I definitely can write simple basic programs...slowly, and rather painfully. Fingers crossed this emulator is much deeper than that!