I suspect you'd have to contact each brand's website, and ask. Assuming they do have a test-drive program, they'd either provide it directly or put you in touch with the right distributor.
I've started to do just that. So far Metcal is working something up and Weller's Northern California rep is on vacation. No luck with the other two companies yet.
JBC does do a 30 day trial through their distributors. Take a look here (
http://www.janelonline.com/Articles.asp?ID=370). Janel is located in NJ though, so it would be done via mail order if you go through them (you mentioned you were interested in a local source).
Never dealt with Ersa at all, and don't see anything on their website about a trial period.
You didn't mention them, but is there a reason not to consider Hakko?
I ask, as the FX-951 seems to offer quite a value here in the US ($262.77 shipped, uses AIO tips that only cost ~$12 per for most basic profiles, and the stand is electrically connected to the station for setback temp & sleep functions when the iron is placed in the stand).
I had to purchase a separate stand (just adds a microswitch and wiring to make it work to the regular stand) to use those features in my Weller WD1 (extra $75, and that was at a discounted rate).
Greedy bastards.