Both Reading and Knapheide offer the "flip top" tray on their "standard" (squared style) service bodies.

There are a bunch of companies out there that offer service bodies - Stahl is another big name here in the midwest, but Knapheide has 'em beat in IL (Knapheiede is in Quincy, IL). There's Warner (www.warner-bodies.com), Monroe (www.monroebodies.com)

Been looking at a 130" setup w/ a sliding top, so I don't have to hang a conduit tube off the ladder rack, and my stuff in the back is "crackhead-proof". It probably won't happen for a year or so, but hey, ya gotta have a dream!