I don't think they exist in the same format - you may get a few ex-pats who have set aside some land for caravans, but they aren't generally a Spanish concept.
I would ask for specific recommendations for smaller sites or look in the back pages of the Caravan Club magazine where lots of Brits advertise their sites. This is not a very small site, but worth having a look at to see if it's the sort of thing you're looking for:
'Can Coromines'
Most European vans don't have batteries, and don't have a 'proper' bathroom, and therefore sites without a hook-up facility, sanitary block, and shop aren't popular with Europeans so not provided in the same numbers. Even the Campings a la Ferme in France are generally provided with a hook-ups, decent shower block, sometimes a little shop, and quite a few have swimming pools.