Unless you're planning on getting a FF body soon, I'd consider selling the 17-40L and the 28-135, and getting the EF-S 17-55mm f/2.8 IS. It's a much better walkaround lens on APS-C than the 17-40 - you get an extra stop of light, IS, and it's sharper, too.
Staying with Crop......I would:
Sell 17-40mmF4 L, (I never liked this on crop. Its not weather resistant unless you add a filter. There is no IS. f4 is relatively slow. and 40mm f4 is not enough to give subject separate on crop)
sell 28-135mm IS - I personally don't like variable aperture zooms (although I do own 1 myself :S)
Buy 17-55 2.8 IS - great quality on crop. and all those dust sucking comments are rubbish as small amounts of dust do not affect IQ.
Buy sigma 30mm 1.4 (as this will be effectively a crop standard. I had this for a number of years on 7d & 60d and it was fantastic)
The above will help in lower light, landscapes (@17) and portraits (55 is ff equiv c88mm)
Keep the 100-400 for wildlife.
Keep the 50mm as 1.8 vs 1.4 is not a massive difference and you wont get much resale value for it anyway.
If you don't use the 100m f2. sell. I've never found 100mm on crop an attractive focal length (but thats personal preference).
Don't bother with the Canon M. Given its size its still not truly compact and cannot rival the speed (particularly AF speed), feautures or quality something like the sony rx100 can provide even though the RX100 has a smaller sensor. Plus a new camera won't make you a better photographer. It'll just be something else that delivers similar quality than your 7d in a slower albeit smaller form.
I cannot comment on the vintage lenses. If you use them keep them, otherwise sell the redundant gear.
Having said all that.................. If you have the appetite to go full frame. Do that. I switched from 7d to 5d3 a year ago and it has been wonderful. The narrower depth of yield at wider angles is unprecedented on crop. so many focal lengths suddenly make more sense, i.e. 24mm, 35mm, etc.. Admittedly 5d3 is a massive spend and might be out of scope here.
With a limited budget. Blank sheet of paper I would:
Sell all your bodies and compacts.
Buy a 6d (if you have 1 camera, that will be the one you take with you. Rather than having 1 main camera, 1 backup and 1 compact; which serve as distractions)
Keep the 50mm 1.8
Keep the 17-40 for landscapes.
Keep the 100m f2 for portraits
Keep 100-400 for wildlife
Keep your 580ex flashgun
Sell everything else that isn't needed.