Ok, so here's what I thought of when I read this idea.
Once you gain suitable Influence with Mandalore/Canderous, Mandalore gets a message from Kelborn on Duxn telling him of a planet with a large gathering of Mandalorians split into two factions. Both factions have the same idea as Canderous, to unite all Mandalorians under the banner of a new Mandalore but neither side can agree on who should be the new Mandalore. The Ultimate goal of this new side quest would be to unite both factions under Mandalore/Canderous but you would be able to side with one faction over the other as long as they gave their support to Mandalore, though, their support would most likely be given only if Mandalore destroyed the other faction.
I see there being both a Lightside and a Darkside way to get both factions to join Mandalore.
I see there being a Lightside and Darkside way to have only one faction join you.
And I see the Darkside path of destroying both clans so that they couldn't be a threat to Mandalore in the future.
I know this idea didn't originate with me, however, if anyone were interested in doing something like this and liked my ideas on it, I would be happy to expand on them if anyone wanted more information.