Bob,
To me, your comments in this thread suggest that your instincts are pointing you toward a 14 footer. For what you have, and your other comments about not adding or changing to something larger, IMHO a 14 footer is your best option.
Sure, having 2, 4 6 or more feet would be nice, provided there were no downside. If you don't need the extra footage, there is the downside of poorer handling, extra weight, wear and tear on your haul vehicle, gas consumption, parking, etc.
I gave this quite a bit of thought, and went with a 14 foot, all aluminum Featherlite, dual axle, @ 7k# GVWR. It weighs in @ just under 1000# and it is a dream to tow. The brakes are awesome, and following some guidelines from other threads in TBN, I have them "dialed in" a perfect match to the tow. My tow vehicle is an '04 V6 Toyota Tacoma 4WD that has a top capacity of 5.5k#
We use the trailer for towing our race car, a Mini Cooper spec series racer + spare tires/wheels, tools, etc., and I'll be using it to haul our PT-425. Oh, someday, we may get a bigger race car or a bigger tractor, but unlike cars, quality trailers don't depreciate to any significant extent if they are well cared for. One just has to look into the auto/moto racing Classifieds. The good trailers hold value. When we moved abroad a few years back, we quickly sold our previous 14 footer for ~$300 less than what we paid after 3 years of good use, and the buyer was getting a bargain when he looked at new equipment.
I don't buy oversize clothes because I may gain weight some day. Buy what you need and, as grandad said: "buy right, and cry once."