Outerlimits, Overlander, 4wdMonthly, Clubs (eg Ozkrawlers), Explore Oz, there are HEAPS of places that are not brand specific.
Just checked a range of brans specific forums:
http://offroadsubarus.com - No other brands
http://www.offroad80s.com - No other brands
http://www.patrol4x4.com/forum/ - No other brands
http://www.pradopoint.com/ - No other brands
http://www.auszookers.com/index.php?name=Forums - No other brands
http://www.aulro.com/afvb/ (Land Rover) - No other brands
etc...really I'm not being elitist etc - but it's a Jeep forum and there are plenty of other places for non-jeeps to be posted up. But that said if there is something of interest on another brand it can be (& jhas been) discussed in General & OT.
If someone has a build that (of another brand) that they feel is interesting enough to members here I'm pretty sure there's nothing stopping them posting up here....heck I'm keen for that build thread of an X90 on 49" Iroks with a GM502 in it .
;)
Anyhow I voted NO cause I think here works just fine without it and it's not out of place with other brand specific forums so why should we be the PC ones.....