I've got an old Burley. It came with a front wheel which I've taken off, but I left on the jogging handle (makes a good rearward cross support.

I think it was a bit of a pain to put the wheel on and off though. I saw one on Craigslist a while ago that appeared to have a place to mount the extra wheel on the outside of the trailer. Looked like a cool idea, but I don't see the ad anymore, so I don't remember the exact brand.