I got a brushroll a while ago, and I've travelled with it a couple of times already. I now realize I never told you about it.
I bought it on Etsy from the lovely Sakura0325, whom I had met on Makeupalley. She did a lovely job for a reasonable price and what I like a lot is the fact that she uses a light plastic on the inside of the roll, so it's washable and the fabric won't get stained by dirty brushes.
I got to chose how many slots I wanted and for what kind of brushes, and I definitely can fit about a dozen in there!
Definitely visit her Etsy shop and contact her if you're on the hunt for a brushroll, as she can customize things for you.
Pictures property of Sakura0325.