The new-for-2008 Highlander has, according to the Toyota Canada web site feature, a 5000 lb / 2272 kg towing rating (or 3500 lb / 1590 kg, like the current Highlander and Sienna, in the hybrid version).
While I doubt I would want to use all of this limit, and the Highlander is still shorter in wheelbase than minivans such as the Sienna, this seems like a promising possibility as a moderately sized tug for eggs in the popular "17 foot" range, with routine loaded weights around 3000 to 3500 lb. Tongue
weight rating is unknown, and would need to be considered, along with all of the other usual factors.