We think we found a horse trailer that at least has all the features we would want and not any we don't.
It's this one from Trails West - only the bumper-pull, two-horse, slant-load version, not the one in the picture. We went to the one of the local dealers, poked around his lot, and this one fit the bill pretty perfectly. Here are the floor plans.
Aside from the basic features above, it's got what they call a telescoping divider, but what that means to non-trailer-savvy folks is that the divider actually shifts over where it attaches to the wall so you can have a large compartment in the back for one horse, or two compartments - depending on who you're hauling. Nice mechanism, says the engineer among us. (Steve, that is.) Not overly-difficult to move, but solid like you would want something keeping horses in place to be.
It's steel, and I know that some people recommend aluminum to fend off rust, but aluminum trailers tend to be about twice the price and since we are pretty diligent about vehicle maintenance in general, guarding against rust will become part of that routine. (But, hey, if I could find a good aluminum trailer for the same price with the same features, I'd take it, too.)
There is a nicely set up and equipped tack room, including a 25-gallon water tank, which will come in handy for what we want to do. (Horse camping and such.)
It has drop-down windows on the "head" side and slat openings on the "butt" side, which you can cover up with Plexiglas during bad weather.
I wanted to mount spotlights on the back in case someone starts to tailgate, but Steve said that it is illegal to blind other drivers.
"How about a poop catapult?" I asked.
Maybe my friends at Make Magazine can make me something that would do the trick. It would have to calculate the angle so as not to hit the windshield and block vision, but to at least strike the hood of the offending car with great gooeyness and splattering.
If the judge I get after being arrested for causing traffic problems is a horse-owner, I bet I only get a mild warning.