I'm moving to fstopgear myself, but it takes ample time, the gear is almost always backordered for months
. I've got my ICU (the largest X-Large was the only one big enough to fit my gear) it took 2.5 months to get, and now I'm waiting for the bag itself (the largest, the Satori EXP). Their inability to deliver which never seems to change has caused many users to become irritated, but once they have the gear most seem very very pleased indeed.
The problem I have with most camera bags is that they are not designed to carry heavy gear (10+ kg) for long periods of time, so usually customizing a hiking or climbing backpack would be better for the types of hikes I like. Here in Sweden there's a strong tradition of walking far in the mountains carrying all with you (sleeping bag, tent, food clothing etc) so we are a bit picky about backpack design. Fstopgear seems to be an exception from the typical camera bags though, their design is very similar to modern hiking backpacks.
I've attached a picture showing a packing example in the X-large ICU. One problem with MF gear is that the sizing is not DSLR-standard so you might need to do some less than fair-looking puzzling with the internal separators. The green ones in the picture I've taken from a different bag. Another suboptimal thing for my Techno is that the Linhof gear has lower profile than the bag itself, so about one inch of the depth becomes unused. I'm going to solve this by having a thin box with filters below the camera body, and store seldom-accessed small stuff below the lenses (extra batteries, spare loupe etc), that way I get more efficient use of the depth of the box. The RM3Di gear could fit better or worse, don't know about its measurements.