Given that the OB lasts a week and everything is wiped prior to the beginning of the Headstart period, I dont think its worthwhile setting a regiment up during OB. More so as we all will be jumping around various races/classes/sides to get a feel for things (assuming GOA behaves!).
If I do find the time to set one up it will be to test the interface and get a feel for the limits of Regiments in this game as opposed to Corps in EVE, Guilds in WoW and Kins in Lotro
Just a thought I had.
(PS we can keep in touch on here for a week and maybe in a custom chat channel if you can have them in game?)