RCPilet,
I'd suggest contacting Larry at Jet Hangar.
[email protected] Most of their jets were designed around the .40 sized DF engines. The airplanes build light and fly great! Also, if you're concerned about altitude, consider this...at the Denver Jet Rally, Larry was flying the new ARF Hawk with a Turbax 48 and from what I heard, it was Haulin! Went well enough to win the "Best Ducted Fan Performance" award.
Also, if you're looking for a plan of the A-10, JHH has one available that is really nice...extremely accurate too.
Chris