you sure you don't want a hard case trunk?
anyways, my lowepro aw backpacker (i think thats what it is) will hold 30d+grip, the fisheye, the flash, the 70-200, the cleaning crap, the 14-70.
its expensive though, and the 400 would be attached on the outside.
goodluck finding that bag . . . why don't you just not carry as much?
buy a 2x converter to get you by in a pinch when you don't have your 400.
i carry a d200 with grip, mamiya 645af, mamiya 80mm, 120 back, 18-70 nikon, 85 nikon, sb-800, sunpak ringlight, 2 reflecters, x-ray film bag(with film), lunch, change of clothes, filters, cleaning stuff, passport, money, slik 700dx tripod, memory cards. in a pinch i could get the d70 in there too i guess. if it rains you safe with that bag. i hike with all of that minus the tripod usually, and take it all on my trips. truth be told though i could get by with the d200 and 18-70 for most things. do you really need to carry that much stuff? probobly not. i carry it all so i don't lose anything, and because i'm out of the country and don't trust leaving gear around places i'm not familiar with.