Look into a Courierware Incognito, size med or small. They can customize and even do some funky cloths for the cover flap. Looks like any messenger bag, not a camera bag.

I recommended the same rig to someone for a Mamiya 6 setup; here's his review on APUG.

Here's the website direct:

http://www.courierbags.com/objects/20.itml/icOid/20

Check out the fabric samples.