Two quick tips on designing your own:

1) Start with the basic lines from a pattern ship you know works really well. These planes have been though many generations to get the performance worked out. Thrust line, wing and stab positions, and incidences. That way you can have a pretty good idea that it will work straight away.

2) Unless you have a real need for a new 2x2 patternship right now build it smaller first. Like 40 or 50 size or even small electrics, that way you don't have to invest as much money and more importanly time when you make changes.

Matt