Welding would be the easy part. Most shops (fabricator or machine shop) would just charge you by the hour and you are probably looking at 30min tops to prep and weld.

What's wrong with the bolt/clamp on? Mine has been on some long road trips but remains solid.

If you were seriously considering that route, I'd look at going even further and build an under boat - frame mount flip down style like Extreme trailers (Malibu) have. Pretty slick and out of the way until you need them.