Recommendations for flashing to cap atrium beams

I'm near completion repairing my atrium beams that had some rot on top. I would appreciate any insights and recommendations for flashing materials to cap the beams with.

The exposed beams are 10' long and the ideal solution is a single piece of metal pre-bent to match the width of the beam and bent down the sides a bit that would drop on top. Of course I don't expect to find this.

Any help is appreciated for where to find this, or a vendor who could custom fabricate this.

Nelson