if the aperture is small, I wouldn't bother with a truss, it may not be effective at small diameters, plus all those connectors would be tiny.
best to fabricate a pvc or wood extension with the focuser removed and then tape the ssag to the fitting.
although I've always wondered what a truss refractor would look like, just having built a truss reflector.!
Something like the Hubble's main body with multiple sections might work.
scroll down this amazing site to see the hubble truss frame
http://www.apollomissionphotos.com/i...le_hubble.html