Exclusiv Modellbau has a 50cc Ultimate Kit, at the moment i'am building the 100cc Ultimate with a DA85 and i can tell you the kit is awesome, nice to build and every things fits very well. The Parts are alle CNC-milled and not lasered thats good for the glue.
The Ultimate is full 3D capabale and also nice in pattern stuff, the airframe is light and turns out with a DA50 aprox. at 16lbs so the power will be plenty.
If you are intressted you can look
HERE! on my website for the buildthread, i think i update the it in the next few days. Like sayd, mine is the 100cc but the 50cc is very similiar in the construction. I find a 50cc Buildthread
HERE!
Some pics of the 50cc version:
