I go back to Janet's earlier recommendation to go to a gathering. The variety of models will expand your horizons. Yes, the corner beds had me almost leaping for joy when I saw the Special Edition features plus
the front bed (FB) Safari. We just about couldn't consider the Bambi, 22-footers or 25' SS because of that stumbling block.
I've gotta love the great air circulation of the open-from-the-top style windows compared to the small Safari windows. My Argosy has those and the trailer cools off to the surrounding air temps pretty quick! I started another thread on the topic but you can't beat the pictures (other models too!) at Colonial Airstream 25' Safari LS SE FB
(yep, they have the wrong floorplan posted...).
With your current tow vehicle you are right to consider 19' and 22'. The Airstream website FAQs do a pretty good job beginning the explanation of weight capacities of tow vehicles, etc. -- probably nothing new with your experience. My wife's folks started with a Starcraft popup, then a 19' Mallard. They gave it up when their snowbird destination (Rio Grande valley) offered cheap winter rentals.
85MH325 Roger is correct about the much higher weights of today's trailers. At roughly the same length my new trailer will be about 1200-1300 pounds more empty weight than my Argosy. I'm staying on the prairies until I solve my tow vehicle needs!
I've got a high-capacity 1/2-tonner (Nissan Titan) and have been by a couple dealers today -- am thinking most about the Duramax/Allison 3/4 ton... My current transmission temp gauge scared me once already -- even with only my Argosy in tow. Minnesota auto dealers have lobbied to keep Blue Laws on the books and that makes Sunday a no-bother lot browsing day! Cool!!
We've got family camping trips behind us but are also thinking of transcontinental trips. You signed on to these forums but that doesn't mean you can't keep wishin' without your Airstream. Just keep planning -- and "do it" on some time schedule that works for you.