I have an English Cape rifle that needs a front sight ... dovetail is 1/2" .. have googled to no avail. Any ideas would be appreciated!

Make one. you'll need a bench vice, a hacksaw, 60 degree file and a flat file or two of different shapes.....

Or a milling machine.

One time I had a Stevens Favorite that some
one had made a shim for the front dovetail.
It was the shape of a parallelogram and fit
tightly.
Good luck!

Yes, I was hoping to avoid having to do that, this is surely not the only 1/2" dovetail in the world (although 3/8" seems to be the standard). I seem to recall sourcing some front sights for a Stevens Favorite that had an extra wide dovetail a few years back, but Numrich is out.