The Tamrac backpacks are nice. I use a 3385 and fit my entire E-PL1, 2ea YS-90, BIG Blue focus light, trays, arms, etc. rig- plus batt's, charger, laptop, and more in it. When fully loaded it's quite heavy, and barely fits in some overheads, but I tend to push it a bit.
The Thinktank products...