Try the largest photographic supply store in D or FW. Manfrotto is Manfrotto. They may even have 1/4-3/8 adapters so you can use your 3/8-5/8 mic clip adapters. If no joy there, call up a couple of large photo studios. Or a large camera store or rental house. Ditto.
Might also give the good peeps at MLD (MLD Equipment Rental - Video Camera & Recorder, Audio, Lighting, & Grip Rentals) a call, and see if they have what you need in their hire stock. Matthews C-Stands work well with stud-to-5/8 adapters. If not, you can head to Guitar Center (or send an assistant) for K&M Booms and stands. Add a second K&M boom to a K&M boom stand's boom for an additional 3'-4' of reach (gets you to between 9' and 12' depending on the stands and booms involved). I do this regularly for support of a pair of MKH8040s, usually with a flanking pair of Gefell M296 omnis. Of course, sandbags/fitness weights/mic stand bases are required to stabilize it. Wouldn't hang M50s or Brauners from a rig like that, but SDC's… no problemo.