Elcan RD - http://www.thehighroad.org/showthread.php?t=515364
I still haven’t used one, but I want one. If you can find one used they’re pretty cheap, compared to a comprable Aimpoint.
An Aimpoint R-1. Same as the T/H-1 series, but silver in color. There’s a sale at Midway for $299.00. Buy a mount and some Krylon, and you’ll be good to go.