I'm actually looking forward to doing it!! I'm even going for a colour change
I did a bit of sanding and filling after work today, the beauty of it is that you don't have to do much masking and can do it as and when you please... The paint cost me £35 delivered and it doesn't need primer!
"The paint you need is Rust-oleum Combicolor. It's an UV resistent, rust-inhibiting paint that will flex without cracking and you can actually apply it with a roller to steel and/or glass fibre - no primer needed. "
Everywhere I have looked, the results look decent...
There's a 148 page thread on painting campers with rollers here:
http://forum.club8090.co.uk/viewtopic.php?f=38&t=18751