In Guild Wars, there is a store purchase that allows you to add copies of your own characters as heroes (companions)
I'd like to see a similar thing done with SWTOR where you can purchase something from the CM that when used will clone one of the characters in your legacy (class/advanced class, name, and appearance) and recruit them as companions.
combat/summoning/cutscene dialogue could probably be copy/pasted from existing dialogue
As far as combat skills go, the easy way would probably be to clone existing companions, however I'd much rather see each advanced class have its own simplified version for companion use