Here's some ideas:
Get a carbon rod with a direct linkage with couplers. Lots on Flight Comps website, but heres one that's M4/M3.
Set - Aluminium coupler for carbon tube Ø 4/M3 right + left + setting ring 1 Set MPJ30064 Made in Czech Republic
Plastic HD linkage
Nylon filled Gold-N-Rods feature an exclusive spline design that reduces friction and eliminates sensitivity to dirt, dust and moisture. They are very easy to install -- a threaded stud screws into the inner rod, and a clevis attaches to the other end of the stud -- and they are versatile, as...
4-40 rod with rolled threads, just make guide supports, you could always epoxy a carbon rod over it and braze a connector on the other end.
Can be used in conjunction with our nylon or steel Kwik-Links or with ball links where extra long pushrods are needed. Bendable and strong. Rods are available 3/4" (19 mm) thread on one end (.093" rods w/4-40 thread), perfect for making custom lengths for your needs. 6/pkg Made in USA
Man that looks like an airplane!!! It's almost this threads 5yr anniversary!