Unlike some generators, Northern Lights has a very good reputation for quality and performance, not to mention a known quality
service organization, so you may have a hard time convincing people to stay away from them.
Only selling parts directly through a dealership network is common - how many parts for your automobile have you bought directly from the headquarters or manufacturing plant? You probably cannot get parts for your main
engine unless you go through a dealer network or other aftermarket source.
It sounds like you are talking about a secondary alternator for
charging a start
battery or some other auxiliary function. Why a regulator would cost more than the entire alternator/regulator combo I don't understand.
However, if this is just an auxiliary alternator connected through a secondary pulley on the main
generator engine, then any old alternator will do - as it seems like you have discovered with the Hitachi.
If you want to get your original rebuilt, just take it to any autoelectric shop.
Is the aux alternator even necessary? If it is just
charging a start
battery, you could accomplish that with a voltage sensitive relay.
Mark