Tons of great ideas and discussion. Experience-based impressions with the Kenti (or any of the bags mentioned in this thread) are much appreciated. Thanks, everyone!
Perhaps I should have mentioned, but additional (even separate) storage for non-photo gear would actually be a benefit for me. That's one of the reasons I've been looking at a lot of camping/hiking style packs, since they're built around that use case. I'm glad that bags designed more specifically for photo gear exist, and I might get one and store non-photo gear in the main padded compartment, but a split design may work better for my needs depending on the design.
From Lowepro, the Protactic 350 and 450 look like possibilities due to the many access options. The tacticool appearance is a bit unfortunate, but at least they don't totally look like your typical boxy camera bag.
@coz, re: front camera harness, I'm a Peak Design user, and I have their attachment anchors, clips, and leashes. I'll likely be doing what you suggest, but with their gear. Good point though!
Lastly, I just realized that when I don't have my laptop in a laptop sleeve, I can always use it for collapsed reflectors/diffusers. Dumb!
Edit: This Thule bag seems closer to what I'm going for. Definitely rocking the hipster/urbanite vibe here! http://www.thule.com/en-us/us/products/sleeves-and-cases/camera-bags-and-cases/camera-backpacks/thule-covert-dslr-rolltop-backpack-_-tl_85854231190
EDIT2: Can't trust their measurements though. Apparently their Perspectiv Daypack has a larger interior dimension than exterior dimension, and Perspectiv Backpack has zero-thickness walls (inside = outside).