The "Do-Everything Car"

Realistically, you've got an '11 Sienna that is (I'm assuming) rated to tow 3,500 lbs (imho, that means you're fine to tow 5,000 lbs; just be careful) and it has a relatively reasonable cost of ownership. You don't really NEED anything else; the Sienna should do just fine. But, granted, there are smaller vehicles that will do what the Sienna will do. Namely the V6 Venza, which is basically the same powertrain as your Sienna (also the same powertrain as the v6 Camry) in a smaller package. So that would be the logical "trade down in size" option for your situation. Also, the v6 Rav4 with the towing package has the same towing capacity.

Some small cars actually have some reasonable towing capacities. The Toyota Matrix is rated for 1500 lbs; if you can make that work for all but a couple days a year, just borrow/rent something bigger for when you're towing more than 2500 lbs. You can even get them with awd.

Also, you could probably email a bunch of (Toyota?) dealers that you'd like to make a roughly even-value trade to get into a smaller, X towing capacity vehicle. You'll probably find one that has a Venza or something like that that's been sitting a while that they'd be willing to swap for your Sienna with less markup than if you walked in asking for a price and trade in value. Just compare your blue book values for whatever is offered to your vehicle.

The Q7 is a large, heavy vehicle with a tight third row. I'm not seeing how it makes sense unless you want the styling and luxurious interior.

Which year Pathfinder? The current one is as large as a minivan, and I'm iffy on towing with a CVT (continuously variable transmission). The older, truck-type Pathfinder might be best for towing, but less good for everything else. Same for the similar Toyota 4Runner.

The 2013 and up Hyundai Santa Fe has a smaller, more agile feel than even a Toyota Highlander, much less a minivan. Plus it has a third row, and is 1.5 inches lower than the Highlander, which is less than an inch lower than the Sienna. So it might best deliver the combination you're looking for.

The Hyundai dealer near me has a couple 2014s left over even though they're already getting 2016s. So they've marked down their 2014s by about $7,000. If your local dealers also still have 2014s, you might get a great deal on a new one.

The 2014-2015 Kia Sorento is related to the Santa Fe, but is nearly a foot shorter in length, so there's less space in the third row and little cargo space behind the third row. The slightly longer, redesigned 2016 rides and handles especially well--better than the Santa Fe--but with any options will be beyond your budget.

The Venza has no third row, but has a much lower roof than any of the three-row vehicles, and even than the Outback (which is nearly as tall as the Santa Fe). It does have a lower tow rating, 3.500 lbs. vs. 5,000 in the Santa Fe or the 2016 Sorento (but not the earlier Sorento). And it only has this tow rating when fitted with the towing package--check for this.

Overall, I'd say Venza or current-generation Santa Fe, depending on whether a low roof or a third row is more important to you. With any of these vehicles, if it doesn't have a transmission cooler I'd have one added.