Hi PiperX,
Being a slim 120kg also, and also trying to move it down I looked at a few home builds, My choice would be a Zenith CH750 for STOL or Zenith CH750 Cruzer, they've been in business a while, good support, good forum, and also additional DVD building support available, take a look as an alternative to a RV, probably easier and quicker to build as well.
Regards