You could do that with the halfpipe, and attach an aluminum hotshoe to it with a simple 1/4 20 bolt. File the bolt off smooth then attach the halfpipe atop the camera using the hotshoe. Mount the camera to the tripod. Camera would stay in place for consecutive shots, easy to exchange lights on top of the camera.
Three-Prong Tee Nuts
If you do want another tripod cheap, I have found the odd one in thrift shops, usually they are missing the camera mounting blocks. They usually go for $5 or so.
Here’s a nice one at walmart for $10.98
http://www.walmart.com/ip/Bower-VTSL1200-Steady-Lift-Series-59-Tripod/16609716
I guess you have a step-ladder already, so how about a couple of sand bags? Hold any size flashlight.
A bag of beans will also do the trick. Get tired of hauling em around, eat em!
I used the DX clamp and a DX gorillapod for this photo:
The Fandyfire UV-S5 was on the tripod.
The DX clamp fits on every camera tripod.