booking.com great sites for foursomes ranked in all your areas
based on budget. www.eurocheapo.com great tips for more budget.

Happy Hunting!

My favs from personal experience average 200 euro/nt for 4

Paris Crowne Plaza Republique www.ihg.com
Interlaken Hotel Interlaken
Florence Boscoloe good for upscale
Venice Boscolo Bellini or Dei Dogi
Rome ihg.com IntercontinentalVille Grand Spanish stops

discounts directrooms.com priceline.com expedia.com otel.com

Have fun!

Thanks to everyone who answered my question with such helpful information!

Here are a few Paris hotels with air-conditioned quad rooms I know. They are in good locations and reasonably priced.

Paris Louvre Opera (Best Western) http://hotelparislouvreopera.com/
Hotel Choiseul Opera http://hotelchoiseuloperaparis.com/
Hotel California Saint Germain http://www.californiaparishotel.com/
Hotel Elysees Union http://elysees-paris-hotel.com/
Hotel Regina Eiffel http://www.reginaeiffel.com/