I've used the Lowepro Bags listed below
Mini Trekker Version 2 (Sold) $123
Micro Trekker 100 (Sold) $? & 02 x Bottle Bag $8 each
Photo Runner (Sold) $?
Linx 160 (Sold) $?
Orion Trekker $? & Utility Case $20+
S&F Light Belt $20+, 01 x Bottle Bag, 02 x pouch 60AW $20+ each
The Mini Trekker is huge and IMO heavy.
It is not easy to access the gear. However, you can store two mounted SLRs. This version came with the tripod holder but no AW. The tripod holder is not very well designed. When you mount the tripod (eg, Manfrotto 190), the legs of the tripod sticks below the base of the bag. As such the bag cannot "Stand" by itself with the tripod mounted. Unless you need it for SLR mounted with 70-200 F2.8, I would not recommend it.
The Micro Trekker is smaller. When attached with the bottle bags
it pretty good for a short hike if you are using SLR mounted with long zoom lenses. However, I still find it very difficult to access to the camera.
The Photo Runner is small. Can be used as a shoulder bag or belt pack.
It can actually store 2 Eos 300 mounted with 28mm F2.8 and 50mm F1.8 lens. Very good for Street Shooting. However, the sling provided for the shoulder is very uncomfortable.
The Linx 160 is the Most comfortable bag among. You can store a EOS 300 mounted with 70-300mm F4-5.6, and 2 small lens and a EOS 300 Body. I sold it because it cannot store two mounted bodies. Unlike the Linx 220, you can sling the Linx 160 on either shoulders.
The Orion Trekker is my favourite bag of all. I actually bought two. It can store two Eos 300 mounted with 80-200mm f4.5-5.6 in the bottom compartment. I can Store a Utility case in the Daypack. The case can hold three small lenses and many small accessories. The Remaining space in the daypack can store 02 water bottles, food and umbrella/raincoat.
S&F belt pack Combo is very very very versatile. I can store 2 SLR each mounted with 28-105 F4-4.5 or 80-200 F4.5-5.6. The bottle bag can store a standard 500ml drink and I also use it to store my filters and accessories. Sometime I add the utility case and another bottle bag to the combo when I go for a short hike. However, you'll find it awkward to carrying around when it is not on your waist.