For the carpool stuff, maybe a big wagon? No third row, but the [link|http://www.edmunds.com/new/2005/chrysler/pacifica/wagon/large/index.html|Pacifica] is listed as seating 5 but the review claims it seats 6 - the Base invoice is $22.6k.
There's also the option of one of the huge old GM or Ford wagons that often had a 3rd row (for tiny tots), but finding one in good shape would be a challenge.
Realistically, a minivan best meets your stated specs. Maybe a used one if she really hates the idea of one?
Luck!
Cheers,
Scott.