Hi Jim
I have run two competitions now on MHF as you say. I have also run many others outside the realm of motorhoming.
The problem I can see with a motorhome forum is that there are so many members with such varied tastes.
Kands has already mentioned the photo rally I ran. It was a very successful weekend and created many threads of interest afterwards. Kands is 100% right when he says it leaned heavily towards photoshop. This was for two reasons 1) the majority asked for it and for me, these days photography is all about photo manipulation aka photoshop.
This diversity leads me to one of the main problems with comps - you will have one camp saying Thats not a photograph, its a photoshop

and the other happily photoshopping everything.
You will then have many varied photographs ranging from maybe a picture of an animal to a stunning landscape - how do you judge one picture against the other. People get very serious about their photography. You will also have members like Laurie with her digital hasselblad and network of macs and then another member with a camera from the biggest manufacturer of cameras in the world - nokia.
Lots to think about


oh and is the comp for the best photographer or the best photograph
Hope the above helps
stew