You can find 1/2" dies for your bead roller pretty easily. For channels wider than 1/2" you can run a joggle (step) die. run the panel through it twice. Once for each side ot the channel. That way, you can make a channel any width you need as well as any shape or pattern you need as I did on my toe boards.
Like this John! This guy kept telling me to come by if I needed to do any metal work and I luckily took him up on it this morning! 2 minutes down the road.... I now have some other projects in mind for that huge plasma cutter bed