I am having ED-E carry a lot of gear, and when I sell to traders, I want to transfer all his gear to me so I can sell a lot. Having to manually click each item is getting really irritating. I don't see a "transfer all" option, or the equivalent. I really hope there is one- is there? Thanks.

PS- if there isn't, does anyone know if any mods enable this?

Tried press A for "take all"? Sometime you can do stuff that isn't appear on GUI (or you can't do it without hoykeys).

There isn't such a take all command in the base game unfortunately as I agree it can get tedious if you've loaded down a follower with a lot of gear.

As to your request for a mod that does this, there is the Phalanx multi-follower and advanced commands mod that does offer this exact feature. Trouble is, however, that it hasn't been updated since mid-November and consequently does not work (AFAIK - many incompatible character file/dialogue/package alterations) with the newest patched version of the game that came out in early December. The mod author has been absent from all his threads in the mod section and on the Nexus as well so this is probably a dead end for you until he resurfaces and resumes development of his mod. Here are the links to the mod page and thread if you're curious about it and want to give it a shot but there are bound to be glitches and errors if it works at all:

http://www.newvegasnexus.com/downloads/file.php?id=35155
http://www.gamesas.com/index.php?/topic/1140476-wipz-fonv-phalanx/

Thanks