I think the perfect couples trailer is actually a shorter rear living fifth wheel with opposable slides in the living area and a slide ward up front for extra storage. The smallest Jayco HT model is only 28' long, which would have about the same footprint as a 24' travel trailer with the overlap, which really isn't much longer than some of the trailers you listed. Being a fifth wheel it would tow effortlessly with the right tow vehicle. It would unfortunately require a different tow vehicle, but it would offer a lot more space and comfort, larger tanks, more storage, full size queen, etc.
http://www.jayco.com/products/fifth-wheels/2017-eagle-ht-fifth-wheels/245rls/Obviously if you're dead set on using your Lexus this idea is a non-starter, but I thought I'd throw it out there as something to consider. My folks are still using a little Nash fiver that's even a little bit shorter and it suits the two of them really well.
