Corner Rounder
I bought one that was advertised in SignCraft magazine and it works great. It ran me about $225 and it has four radius settings. It will do up to .080 aluminum. You need an arbor press - I bought a cheap arbor press from Harbor Freight for $50. This thing works great. And no, I have no affiliation with this item - I just bought it and it works perfectly.
What I like is that is has 4 radius options all in one unit. I can look up the company I bought it from if you want to check into it.