I have a frame without the drill outs for the rear brake

The rear wheel is a single speed freewheel so I'd like to have front and rear brakes

Does anyone have picture of a clamping system on the chainstays as I won't be drilling out the brake bridge

pretty much like these brackets but since I already have brakes don't need the calipers

Seems easy enough with a few parts from Home Depot, a drill and some tape where it contacts the frame

Why not just drill the bridge? I'd rather do that than sport that monstrosity^^

when I get a set of track wheels and a cog, I'll be dropping the rear brake

anyway, won't drilling brake holes into a track frame send me to purgatory?

Don't drill the frame.
Don't use that ugly ass bracket.
Don't ride the frame until you have a track wheel/cog, or just use the front brake, like most people do.