In Fallout 3 there was a command to strip an NPC of all their items, but this doesn't seem to work in FalloutNV.
Has the command changed, or can it now only be done with the unequip command? I'd like to change some of
their outfits, but the ones I want them to wear have little to no DR, so they won't wear them. Any help would be
appreciated.

You can only remove boones outfit before his quest rest you need console commands

Easy:

Open console
Click on the NPC whose inventory you want to manipulate
write "inv"; a list of the stuff the NPC is carrying is written to the console.'
use command "Removeitem "

That allows you to get rid of companions permanently worn clothing. If you want to add it back you have to use the "additem " command, and look for the ID's from http://fallout.wikia.com/wiki/Fallout_Wiki.

Or just use this mod: http://www.newvegasnexus.com/downloads/file.php?id=36220, it makes comapnions clothing removeable and wearable.

Thank you very much!