If you're happy with non-fieldpro you can definitely get good deals on late serial number EL SVs, particularly the 8's and 10's. The 12's seem to be holding their price more.
When I got my ELs, I went out of my way to get new-old-stock of the pre-FieldPro version to get non-proprietary strap mounts. Also, if you get non-FieldPro, you are guaranteed to get one with the close-focus ability before they were gimped to not compete with the NLs.