Looking for an old, flat hot rod glove box door

[glock35ipsc]

OK, all you familiar with the older cars & trucks (30's, 40's, 50's ??), I need help locating a glove box door, and have no idea of what older vehicles might have something close to what I am looking for. It needs to be in the neighborhood of 15"-17" wide, and 5"-7" tall. Needs to be flat, no curvature at all top-to-bottom or side-to-side. Squared off corners are OK, but would prefer something rounded. Basic shape should be rectangular, oblong, or wider at the top than the bottom (like the OEM door).

I hope this makes sense There are just enough fluctuations in the OEM 67-72 doors on the rolled edges that make it not sit flat to the dash without some gapage in various places. At least not flat enough for me. I could weld another piece to the back and fill in the gaps, but I am also open to the idea of using something totally different.

For those that haven't seen my build thread, I took an old stock door and sectioned it to better match the size of the new gauge bezel: