I went to a big store nearby so I could measure it up with my Caanoo. It's a 'Game Traveller' from RDS Industries.
There were a few soft cases that looked like they would fit, so I would think any soft case will be ok - though please note that I had to trim all the internal plastic that was DS-specific.
As for hard cases, they tend to be a little 'tighter' to the console, so if you can't get to a store I'd say go with a soft case.
Good luck!