Well, I didn't want to say anything because I didn't want to take a sale away from a YT vendor (Cindy - chattiesmom), but since you said the Go Doggie bag wouldn't work for what you had in mind...before Cindy came out with her Go Doggie bag, I ordered Sukoshi a diaper bag from a seller on eBay. It is actually a baby diaper bag, but you could definitely use it for grooming supplies. The seller's name is Teresa, and she was SO great to work with! Her bags have pockets inside to put all your brushes, etc., and although her standard bag wasn't big enough for me (I knew I'd be taking a LOT of stuff home for Sukoshi at X'mas time), she worked with me and made me an oversized bag that is PLENTY big
. You could use the link to ask her a question, tell her what you're wanting, and I'm sure she'll make it to whatever size you'd like. I got an oversized version of the bag below, with "Sukoshi & Tanuki" embroidered on it (in preparation for getting Tanuki next May), but she has other fabrics available in her store if you're prefer another color scheme...
The bag like I got for Sukoshi in the "non-oversized" dimensions... Deep-South Designs - eBay Store
Edit: This listing has a pic of what the pockets look like inside...
Pic of Inside Pockets