I've had a hard go at it. My plan was XP Home/PRO RETAIL/OEM MCE VISTA x86/X64 W7 x86 X64 Server 2008 on one DL DVD. This was of course quite too large. I took off MCE, 2008, and all non US versions that I'm not likely to encounter(i.e Vista Starter, W7 Home Basic, N versions, etc). Probably room for something else(except 2008) if I dropped the XP stuff(~1.3GB) For XP I used XP powerpacker and made ISO copied contents to the root of the All in ONE ISO. Edited the BCD to point to the LOADER.BIN of the XP disc loader. Exported the WIM's from the thier source disc, to an install.wim. Used imagex /split wim to 2GB swm files since I couldnt use UDF file system as XP setup just loads way to slow. Then for ocsdimg made a bootorder.txt and used -yo switch, and -m and -o. File size came in just under a DL DVD. The issue I have ran into for what I was trying to do were: If i used W7 disc as source, the bootmgr couldnt find loader.bin. If I used Vista as source all was fine. Really more just the boot folder and bootmgr difference I guess, as i copied those from Vista onto W7. I'd rather use the W7 as source and use the boot.wim from that. Another issue I seem to be battling is if I use W7 source with my "all in one" wim, all W7 images load and complete install, but Vista ones fail after image installs and decompress, and setup starts I get the windows can not start the installation. Conversely if I use Vista source, then the W7 install errors out at same place. I cant be sure but it seems like I had it working fine when I just exported say vista wim into already present W7, but if I exported from both to a brand new wim I got this error. I think I read that the wims are of a different structure and this is apparent when just using the /info switch. Maybe have to use the reverse proceedure for vista inside a w7 VM like for adding a service pack, capture the .vhd to .wim that way the Vista image is built with W7? Either way i believe it is possible to do if you pick and choose your OSes you want, but definetly no way to have them all for DVD, USB and Bluray I think it would work fine. I actually came here looking to what I might be doing wrong with my setup, when I saw your question, I know some people have claimed to have done it so I'm sure it works but I'm not 100% sure on the how.