you are going to need something big !
i have a lowepro nova 4aw shoulder bag which is kind of large ...
well large enough for a dslr, 5 large lenses, a meter and spare body
but with all the dividers removed my series D fits in there ( on its side ) snugly.
i have travelled to europe this way with this as a carry-on there are pockets on the outside and a large pouch
but it isn't big enough for a bunch of holders and meter and an extra lens ... i have another bag with all that stuff.
if you can find bag-mags grab them! they are compact and much easier to lug around than film holders ...
good luck !