FYI I've never built or used a hog trap but there is some good information on traps and trapping, bait, etc. at http://www.tpwd.state.tx.us/huntwild/wild/nuisance/feral_hogs/#trap
(I'd be glad to help someone build one)

If you haven't already, you might check out all of TPWD's info on feral hogs....good stuff. Ray