So, here's a tossed out list of specs that I can think of.
-GOOD nylon cloth. Ballistic would be cool, but either way, something durable. More durable cloth on the bottom, and the sides... because the sides will become the bottom.
-Long enough for the 1900 rail that comes with the TS 75.
-The two main sections of the bag should be sized so that a sys-mini, or a short stack of them, could be placed in there for small parts and such. One of the compartments should be dimensioned appropriately.
-Main bag will have two nylon straps that go all the way around the bag, and terminate in handles. That way, the bag in its entirety can be closed up and moved fairly easily over short distances, and be held closed by the straps while it's being moved, without the need to completely zip everything back up. I also think that there should be handles RIVETED, AND SEWN into each end, for 2-man carry. This is going to be a big bag, and it just makes sense to set it up so that 2 guys can carry it if they need/want to.
-Clamshell design. The main bag unzips, and flops open along its length to show two main compartments, with zippered doors along the full length that are closed. These doors will be padded, as they will surround the guide rails when the two halves of the bag come together. I think this is a critical feature of operation, because there will be times when we just need/want a rail, and it should be the first thing we get to when we open the bag, without having to dig around. I don't want a re-hash of the OF-1400 systainer, where the router is sitting in something that looks like an 8 year old's bedroom, no matter how it was designed to be put together. Immediate rail access is key.
-Once the padded doors described above are zipped open, the back of the door should have WIDE, buckle-adjustable elastic straps for holding long items like parallel guides, MFS rails, MFT fence parts, etc.
-Individual padded compartments in the main bodies of the bags should be equipped with buckling nylon straps to hold everything from Geckos to mini systainers, clamps, rail guides, and stops for jigsaw and routers, the rail protractor, sys-minis full of bits, blades, etc. At least one of these should be a compartment that zips completely closed to hold small parts and tools that would otherwise rattle around.
-There should be a simple velcro-flap pocket on the outside of the bag to hold an inventory list, so that there's a way to know EVERYTHING that is (or should be) inside the bag before you leave the shop, or leave the job-site. No head scratching allowed... this stuff is too expensive to leave that to chance.
-Some kind of semi-rigid shell underneath the cloth on the outside, so the thing doesn't sag too much.
I'm imagining that the upper limit for the price should be what Festool would normally charge us. The difference is, this bag will be more useful.
What am I leaving out?