I found the only drivers to add to boot.wim are the 32Bit versions of the masstorage drivers the 64Bit ones wont work. the rest of the drivers IE. chipset, lan including masstorage. should be added to each index of the install.wim Not forgetting that the 32Bit versions into the X86 install.wim and the 64Bit versions into the X64 install.wim. Doing this will not greatly enlarge the size of the final install.wim My AIO came in at just under 7.2 Gig and thats with SP1, IE9 my drivers for both X86 And X64 plus 250Mb for The X64 Recovery Enviroment and 1.5 Gig for my Apps.
i think that compression was not used. iv'e added 4.15 GB worth of software , all updates for win7 plus winlive, all updates for office enterprise 2007 SP1, SP2 etc etc, and after using /compress maximum for every image i captured (8 in total) i only ended up with a whopping 7.45 GB of AIO install.wim and yeah, i slipped IE9 a while ago, installed from that image so it was already added Forgot to mention that this was all done from win 7 SP1