Vault 87, meeting Fawkes:
http://i70.photobucket.com/albums/i86/deadlykris/Fallout%203/Roberta027FawkesV87.jpg
http://i70.photobucket.com/albums/i86/deadlykris/Fallout%203/Roberta028FawkesV87.jpg
I use the nvde version of BABE Mk3, but I was browsing around in the G.E.C.K. the other day and ran across Item #89B52 - "Underwear." I don't believe it's used anywhere in the actual game, and the Wiki doesn't even mention it. So I thought "hmm..." and downloaded the Underwear version of BABE Mk3, extracted the mesh, and plopped it into the path for the Underwear item. Then I fired up the game and it looked a little off, so I grabbed the underwear textures (but not the skin textures since I already have them) from the archive as well, tossed them into the right place, and result: http://i70.photobucket.com/albums/i86/deadlykris/Fallout%203/Roberta029Nothingbutherundies.jpg The item is an outfit, so you can't wear it with anything else, but it works for my purposes: I don't have to http://i70.photobucket.com/albums/i86/deadlykris/Fallout%203/Roberta030SallyMZ.jpg in the buff (ok, yes, that's a bit past the moment of rescue, but by the time I actually rescued her I had found some Enclave clothes for my character to wear anyway)! I just made a batch file to add it via console (it also removes any existing Underwear items in your inventory, and auto-equips the underwear).
http://i70.photobucket.com/albums/i86/deadlykris/Fallout%203/Roberta031Secretstorageroom.jpg
The Underwear item appears as a Vault 101 Jumpsuit on male characters, as well as when dropped by characters of either gender.