SIG's Fazer LG is the bargain deal; maybe available at your LHS. Brodak sells the same piece under their own label, I believe. If you look in the vendor's forums below, Steve Wilk has two grades of CF LG struts. They are the same except for the spendy one has carbon cloth on the outsides, to prevent splitting. Should work for 11" prop, but might get close if you don't plan ahead. Perhaps somebody has used them on a Twister and will chime in?
Steve