Like so many other folks who like photography, i've accumulated about a half-dozen camera bags/packs. Of all of them, the only photo bag that i really like for Medium format is my Kata 3n1-30. My medium format kit is a RB67 Pro-S, 65mm and 180mm lenses, extra 120 magazine as well as my light-meter, film and a couple filters (plus small notebook, pens/Sharpies/soft-cloths/etc).
A life-long hobby of mine is backpacking and over the last 30yrs i've used most of the major brands on the market to compare with and i must say photographic backpacks have a loonnnnggggg way to go to catch up to the load-bearing requirements that come with Medium format. The Kata 3n1-30, while the best one i've used thus far (including various LowePro packs) suffers from insufficient shoulder straps. LowePro packs have much better shoulder straps and comparable (or better) pack fabric (but the zippers aren't as good), but i do not like to stack my lenses in a vertical position.
What i'm using now is a large-ish day pack (about 3,000 cu.in). It's an olive-drab color (definitely *not* pleasing to the eye....), but doesn't scream "EXPENSIVE CAMERA GEAR INSIDE - STEAL ME RIGHT NOW!!!", is made to carry hefty loads and is very durable. I store my lenses in neoprene padded cases and the other assorted gear in the various pockets.
What i am now looking for is something padded to store my RB67 in (inside my day pack). I may have to stitch something from neoprene myself, but i believe it will be well worth it because then ANY good pack will suffice and i don't have to rely on expensive "photography" packs to haul my gear.