I think there's a huge gap in the market for a website aggregating listings for motorhomes and campervans for sale.
There are over 180 keyword/phrases around or related to 'buying a motorhome or campervan' - 110,000 searches a month and it's something like 30p a click. They sell for anything up to £70/80k (and the rest).
There's no-one really doing it. Autotrader try to do it, but they're just shoe-horning motorhome listings into a car selling website. They don't cater for all of the bells, whistles and options that you'd want when searching for your perfect motorhome.
All of the other sites are just individual companies trying to sell their own stock.
Huge market if anyone has the appetite to have a go at it. If I was younger, I would definitely consider it ;-)