Sorry to be the bearer of sad news, but the vast majority of Airstreams, both TT's and MH's are made for only two people.
We have a 2005 ASLYG 30 SO. I am 5' 5" and just barely fit on the sofa when lying down. I have to take the armrests off in order to stretch out.
We had the dinette originally, but swapped it out for the permanent corian table. The dinette, when folded down was way too short for anyone but a child or petite adult to sleep on.
Don't get me wrong, we LOVE our MH! It's just that it really only fits two people on the "queen" (which is shorter than our queen at home) and maybe one on the sofa.
When our kids come along, the first thing we do when we get to our site is have them pitch their tents. The DW and I then get the MH all to ourselves.
Good luck with your search.
Bob & Nancy
2005 ASLYG 30 SO
2009 Wrangler Toad