Another way is to design it using a straight piece of tube,then use handrail fittings(bends etc) I've done this at work . You can get fittings 45 or 90 degrees,they fit really tight and butt up tight only showing the join line and the od is exactly the same od as the tube,not a big gap,and might not even need welding if you make the tube the main 'stressed part' of the bumper and the ends as trims,also available are caps for the ends.The bends slide in to the tube about 2". I use a high strength glue to stick them together.....yeah it really works!

,and not as bad as you think, to look at.Give me a pm if youre interested and I'll sort out more info etc.