As for a player nomad faction,
it would be possible to make a "nomad" player rep. The catch is that all the other factions will hate you since you're a nomad and want to rid Sirius of humanity. Period.
On a personal note, I think a player who adjusts their rep by shooting enemies of the nomads to get friendly with them should be considered a traitor to humanity(imho) and their rep adjusted so all of sirius hates them. Even the nomads wouldnt trust a traitor and I would suggest their rep be no greater than barely neutral so they cannot buy nomad weps.
As for NPCs following player ships...
well they already do to an extent, but there is a mod the allows them to follow you anywhere in a given system..the catch is they cant follow you into other systems. I think that would have to be coded in.
For the time at hand, just plain going out and hiring other role players as wingmen is the best option. At least you have to pay them. NPC's on the other hand...I think I would stay away from that can of worms...its a cheap cop out by not paying for your help. But if NPC could be coded into the MP game to be bought as wingmen..(I know, I've seen it done in "Tachyon: The Fringe" and that's a whole different game engine) I would see to it that it cost just as much as hiring a real person. Besides, NPCs just dont have the same skill level as real players do.
AKA Retread
"Where WAS that jumphole from the other run?"