Well, there's no saber customizing. (As in individual parts). That indeed would be a large undertaking. There will just be a lot of saber schematics to choose from.
Mine and Canderis' goal is to have schematics for all the Jedi Masters, all of the Sith Lords, for each prestige class and for each basic Jedi Class.
I figure party member sabers could just be filled in by USM sabers.
Eventually, we'd like to get all of the USM sabers ported over and a good number of HOTOR sabers.
Ideally, if we could get every saber ported over that'd be cool, but it'd also be cool to get people to contribute more sabers and make it sort of a community driven mod.