It can be done, but it's all about balancing how much it would be used, versus fragmenting all the content of this site.
In terms of usage of this site, it would make more sense to create a Southhwestern US site, a Northwestern US site, a Rockie Mountain site,... In my opinion, it starts to split the content too much. I don't see how location changes what we're all interested in, Sportsmobile / 4x4 / camping vans.
Now for trip reports, I could see some benefit of creating geographical sub-folders.
SMB-less as of 02/04/2012. Our savings account is richer, but our adventures are poorer.