I think that most RPGs or other games set in fantasy worlds follow the algorithm suggested in the rulebooks for Swedish PnP system Drakar och Demoner. Take an existing name, add a few "h" and swap a few other characters. -bar must be an incredibly common last syllable in fantasy names. Either that or you give the character a name that actually means something or exists in the real world (the M&M approach). And try to make the names sound similar (Gothic uses a lot of Spanish names for instance). Some games simply steal real names that noone heard about (IIRC the demo for one of the Krynn games has characters named after Latvian and Lithuanian cities).
So I dont think there is anything profound to the Rhobar name. It's likely just a mutation of Roger or Robert...