4-40 pushrods have much less flex than the 2-56 stuff, I’ve used the pushrods and the solder on ends below with good results they're just a little more work than the 2-56 stuff with the plastic ends.

4-40 pushrods
http://www2.towerhobbies.com/cgi-bin...&I=LXD871&P=ML
4-40 solder ends
http://www2.towerhobbies.com/cgi-bin...?&I=LXD895&P=M

If you want the very best money can get, check out the link below for carbon fiber rods with 4-40 titanium ends. I use these on my 33% Cap and I’m putting them on my 65” OMP yak when it’s done.

Carbon Fiber phushod kits
http://gallery.bcentral.com/GID50514...DS.aspx?page=1