Another one, just mentioned by dsl on the main site, with a slightly more upmarket selection: http://www.studio434.co.uk/index.php (I'm amused by how their selection of properly flash cars is augmented by a Plumber's Van and how they have no less than 14 Aston Martin Lagondas.)

And another one I've remembered: http://www.a2ecommercials.co.uk/