Radiator covers

So I took the ugly metal cover off of one of my two radiators, to look and measure. Here's what I saw:

Not what I expected. It's not very tall, and it's set into a preformed metal  niche under the window (the upper boundary of which is a metal windowsill).

So I can't have the sort of boxlike custom radiator cover that doubles as a windowseat. This will be simple: I just need attractive hinged doors to replace the ugly flat metal cover. (Why hinged? Ever live with radiators? They create dust - who knows how - so you've got to be able to get at them to vacuum. This one has obviously not been vacuumed in a long, long time. There are feathers in it!). I believe the doors can be wood - I know they need to be slatted, or have holes in them somehow, so that air can circulate - and I hope they can be pretty.

The space is 64.5" wide by 28" high. Ideas welcome.

The metal windowsill, I'm not sure what to do about. It's been painted  a zillion times, and looks worn, but on the other hand I think it's an integral, welded part of the radiator niche, so I can't mess with it. Can I refinish it somehow - or cover it with some sort of thin veneer and edge molding?