The rack on top is a TMS truck ladder rack, I just changed the orientation of the pieces to increase the height over the standard 30". That added height allows me easily float the kayak off the trailer. If I had gone with the recommended orientation, the kayak would have gotten stuck under the rack when launching. The basket on top is a TMS roof cargo basket with extension. Cabela's sells the same rack...in fact the extension itself came from Cabela's on sale.
Most of the ideas for the trailer were just me expounding on other people's ideas and making them work better for me. The most innovative thing I did was mount Rhino Rack saddles on custom unistrut mounts to offer side support to my kayak when trailering or storing. Not that I really store my kayak as I fish year round.
Here is a picture of why I mounted the ladder racks the way I did, you can see that even as high above the kayak as the rack sits, I still have to close the seat to float the PA off/on the trailer if the ramp is steep.
Here is a better picture of the trailer itself. No, I don't trailer with the mirage drive in, but I do store it that way.
Oh yeah, you asked about rust. I sprayed the Harbor Freight trailer with Rustoleum as I was building it, and any time a spot creeps up I clean it and apply a little more paint. About twice a year I give the whole setup a once over, check the bolts and harware for rust and fatigue and give it a light spray of paint.
Let me know if you have any other questions. And hurry up and get your Hobies, your missing out on some good times.