I've made die sections from a brake formed channel with a brake formed vee. for large radii the tonnage is very low so the dies hold up perfectly fine for production parts. (We have several hundred uses out of one). Easy to make a punch with a piece of rod. I'll draw up a concept real quick.
That way works, making rolla bee dies is not that hard. I have made them from 3/4 and 1 inch bar with 1 inch holes drill, then spit the hole in saw, then take 45 degrees out of that 180 hole. Weld the saddles onto a plate and use a split 1” round for pads. The saddles can have a just less than 1 inch space between them. Works pretty good.
I recently made some milling a 5/8 diameter saddle into square. Fully supported 5/8 cold roll split for the pads. I just weld the die blocks at spacing wanted for bend.
Rolling dies Can run a lot closer together than vee gaps. You get a nicer/truer radius (not the parabola of air bending). Once you make the switch it is hard to go back to fixed vee for any bending.
You can get complicated and have the dies roll in on gear so they act as boost pressure, leaving less thinning of bent part. Not an issue with larger radius bends.