My guess is that the reward is the Pip-Boy 3 Billion. A "blinged" version of the Pip-Boy. :facepalm:
It was mentioned here: http://fronttowardsgamer.com/2010/06/03/front-towards-gamer-radio-episode-7-larry-liberty-senior-developer-for-fallout-new-vegas/
Everytime I see this, I imagine some Saints Row ghettotastic diamond studded piece of crap, and I can only express so much horror at that thought. I'm hoping that just means it's got some unique USEFUL features.
I think they said that there are no Stat increasing powerups like the FO3 Bobble-heads in New Vegas. But I think a http://i271.photobucket.com/albums/jj125/Gizmojunk/VB_Snowglobe1.gif could look cool.
Spoiler
Of course it goes without saying that that picture isn't official. That's one of my forum avatars.
Only reason to collect collectibles is for some form of reward. I'm glad that it isn't skill or SPECIAL boost but if there ain't a reward good enough the only reason I'd hunt for them is for the achievement and because there is a guide at the wikia.
I wonder what they'll be of though. Vault Boy was really overused in fallout 3.
I highly disagree Vault boy is amazing and when you find a BA animated dude like that you use him. Besides, he's always pretty humorous.