I read with interest your report on the Highlander. The 'tow package' such that it is does not include a transmission cooler. Have you at anytime considered purchasing one and/or was a transmission cooler ever part of the conversation when you put together a tow package?
I'm leaning toward purchasing a Highlander for many of the same reasons you have. "We had other reasons for buying a mid-size SUV at this time. Towing is only 10-20% of our miles per year."