Are there hotels in Cassis other than those listed on booking.com, tripadvisor, or expedia? We are looking for a place for 2 nights (midweek) in August for our family of four and striking out on all fronts. Surely there must be other options to contact directly or via another source? Appreciate any guidance!

You can use guide books to find hotels. That's what I normally do.

Here's one I found by clicking on "destinations" above.

http://www.fodors.com/world/europe/f...iew-51019.html

You can also use google to find hotels. Have you searched on this board? There are lots of ways.

Also, check B&B/Inns on Trip Advisor in Cassis. I had trouble finding accomodations too and ended up booking at L'avila Cassis, which looked stunning.

aside from those methods, the city office of tourism usually has lists of hotels (I know they often do in France). here's the one for Cassis

http://www.ot-cassis.com/en/hotels.html

The Cassis Tourist Office has ALL the accommodation available and you can use the online booking service (doesnt apply to all properties though). Consider the Chambre d'hote...
But be quick, it looks like you're coming with the crowd and hotel are filling up quickly....