One thing to consider, that I think many of us fall into on the first go around - certainly my wife and I qualify
- is that we started out thinking we'll never get rid of this trailer. Why would we? It's our dream trailer - perfect, small, cute, and you can tuck the little thing anywhere.
This happened with our first Airstream - a 19 foot Globetrotter. We made big plans, towed it cross-country... and by the time we'd actually spent a couple weeks in it, we realized we didn't looove
turning a sofa into a bed every night. We didn't neeeed
the whole rear end cap dedicated as a bath and shower. We needed a bit more storage. A few more feet.
11 years later, we're halfway through a full renovation on a 22 foot 1950s model instead, with a small wet bath and full-time queen to fix our previous complaints. Even now, might we someday wish we'd sunk this time and energy into a 24 footer? Maybe. We think we've got the balance right for comfort and ease of towing... but who knows!
So, keep that in mind too. I don't know if this is your first Airstream... but they're kinda quirky! From one era to the next, and all the various layouts and dimensions? Definitely worth spending a few weekends in it before you break out the drill and tin snips, if possible.
Another observation - which isn't fun, because it would involve completely starting over - is that a steampunk Nautilus-themed trailer sounds awesome: but it could be a case of "more is better", in what you could achieve with 28 or 29 feet of submarine vs. 16. An old Sovereign
or Overlander could be pretty sinister with riveted fins, a row of portholes... etc. Just stuff to think about.
Keep having fun!