I stumbled across this Oregon business Equinox Trailers and I'm very happy I waited. I have 2 thirty pound dogs, so it's not a weight issue, but a layout concern that kept me from getting one of the typical pet trailers. I looked at new and used pet trailers for months before coming across this website.

I took the trailer out Wednesday for a shakedown ride and it's very well behaved. One thing that showed why it's good to have a custom trailer, is the owner redesigned the divider in the trailer to attach lengthwise, instead of his standard width wise partition.
Now my dogs can stand more comfortably in the trailer and although no one had asked for this configuration before, he came up with a solution that works very well and did not charge me extra.

The trailer can adjust to 3 different widths and if I take out the center divider and the floor, I'm pretty sure I don't ever need to use a car to go grocery shopping again!
I can haul as much in this pet trailer as we've ever put in a vehicle and the pictures he showed me of what these trailers can haul make me confident it can haul what I throw in there.

I can't recommend this company enough. I don't have a public site I post pictures to, but PM me, if you'd like and I'd be happy to send pictures of my trailer, hitch and bike.