Since everyone can voice an opinion...
A seperate forum may be easily over looked by some. I usually only come by the tech "door" and only ocassionaly go "next door" if I haven't visited in a while. I'd likely never visit a "swap" forum. My point is, unless one uses the Main entrance, via a bookmark, the door used will not have any indication that there is anything to swap. Secondly, with so few active members, I think you'd have better and quicker results on a local board even if that's at a grocers or pharmacy.
Another alternative is to have a 'sticky' on the Community forum. But those are usually reserved for matters of continuing importance not casual commenting.
Basically just offering suggestions...no problem with almost anythng that is decided.