Only two:
Dr. Pepper Park (Frisco Roughriders, AA of Texas Rangers)
LaGrave Field (Ft. Worth Cats, independent)
LaGrave is pretty cool in that it was rebuilt on the same site as the old, historic LaGrave field, and the excavated dugouts were incorporated as field "suites," so essentially new LaGrave Field has four dugouts. It is also laid out exactly as the old stadium, with home plate at the exact same location.
I have also been to Majors Stadium, the site of a minor league baseball stadium in Greenville, Texas many years ago. Only the front gate (with ticket window) and adjacent tool/work building are all that's left. The gate is really cool, though:
http://www.ballparkreviews.com/templ...in_state=Texas