I likely have one; I will need to dig around.
Postage form Canada plus perhaps $5?
(207) is Maine, I believe. I can't find too many other clues as to where you are at to see what might be involved to get one, if I have it.
I do have a 20x24 drum, with a ton of ribs and stoppers so your 5x7 backlog could be over in a flash. Actually I am not sure it has enough ribs and stoppers to load it up with 5x7.
Most of my roller drums are Simmard, which was a Canadain importer of days past. I consider them of eqaul qulaity to Beselar and Unicolor, for I have a few of those hiding here or there.
My drms do not see much use since I put my roller processor into service a few years ago, but I keep a few around for the day when the rollers becomes unrepairable.