I built a run that was 9ft x 4.5ft with a 6ft x 3ft hutch that sits on top. I'm afraid I don't have a photo at the moment though, I will probably post some after this weekend. The run was made in the style of aviary panels but a nice thick wood so that it would bear the weight of the heavy hutch. Because of the odd shape it needed an extra support stilt inside too. If it had been a 6ft x 6ft run I don't think the stilt would have been needed and it could have just sat on top of the run.
I could post photos of the hutch and panels during construction if you like, I just don't have the photo of the hutch sitting on the constructed run.