Im looking for resources ala hotels.com but only for villa rentals. Does anyone know of any good sites like this?
In Belgium try http://www.belsud.be
For France, a great site for renting farmhouses in coutryside or small villages is Gîtes de France.
I'd take a look at Air Bnb, it's starting to really appeal to me for big bookings, or for non-standard hotel bookings.
In Spain the biggest (and also the one that offers better prices) is idealista. You can try to find by "rent" "holiday" in any of the country areas. Good luck.
The largest such site is http://homeaway.com, which is a big roll-up of many smaller sites that got bought by the same company.
Another good website I found was this: http://www.provacances.com/