I put thousands of miles on Granite Gear Virga Backpacks — before finally switching to the awesome (but expensive) Hyperlite Windrider.
I feel the black Hyperlite is the best looking light backpack available.
One complaint I had with the Virga line was that they were the ugliest light pack on the market. 😀
The Granite Gear packs — however — are now offered undyed.

Read a GearJunkie review.
Very cool.
You can decorate an undyed pack any way you like.
The Virga 3 is also possibly the most adjustable backpack on the market, as well. AND inexpensive.
Click PLAY or watch it on YouTube.
I could happily go back to the Virga 3 using my inflatable Therm-a-Rest NeoAir Uberlite as the ‘frame’ support.
I’d decorate the pack with the ‘theme‘ of my trek.