Music video I made for a bend called "Nizbrdo" from Majdanpek, Serbia, last summer.
http://vimeo.com/84665301
It was a struggle to do it in Kdenlive, but since I was not in a hurry it all went well. I didn't made proxy's for HD videos, but even with DV material when effects are on realtime playing is difficult. I've used i3-550, so it is not that slow CPU.

Also, I've made few report DVD's for "Sound and Visions" festival over the years, exactly for 2011, 2012, 2013. I edited the DV material in Kdenlive, exported it as MPEG-PS and authored DVD with DVD Styler. Editing DV material in documentary style is really easy with Kdenlive.
http://www.youtube.com/user/SOUNDandVISIONS2010