I just picked up a free Jet Ski and I had foolishly thought my current small trailer (4x6) would be able to manage it in the short term. But with its sides and rack setup it did not fit very well.
I'm considering buying one of those 40x48 and modifying the frame to be bigger. The axle width and capacity would be perfect. It's a shame because I remember one on here for free a few months back lasting a lot longer than expected.
Cheaper the better a new kit is around $500 shipped and used jet ski trailers seem to start at 500 and go up. I'm in CT