I've got a 24' enclosed Featherlite trailer. If you didn't already have it, and you plan on replacing it with the same setup, the load distribution bars help alot. It really helps to settle down the trailer.
http://www.reeseprod.com/ Look for weight distribution under the Products tab.
I'm the absolute master of flat tires on trailers. I don't know how or why, but I usually get at least one when going cross country with a trailer. I always check pressures, I always check for odd wear, but I must just manage to hit something every time. The worst is when the front tire on the trailer goes, and it takes out the back tire. Glad you had the bars, I know exactly what you're talking about when the trailer gets squirrely with a flat.
Sorry for the troubles, that sucks.