I believe Dover and Smartpak order from Phoenix West. Look into just who their supplier is.
Phoenix West used to be Warner’s Tack Trunks back in the day. They are the West Coast’s answer to McGuinn Farms.
I have a trunk of theirs that dates back to 1990 or so and it’s going strong. I have seen McGuinn trunks, but not worked around a lot of them. I think their quality will be comparable.
All of my trunks and equipment is from Warner’s/Phoenix West (because once a company has your artwork on file it’s easier to have them continue to make stuff for you).
A couple of years ago, when Smartpak was having a 15% off sale, Phoenix West products were included and I ordered some trunks then. Smartpak took my order, but I noted that it needed customization. They got with Phoenix West, I confirmed what was going to be made (even modifying the inside of one of the trunks) and it all arrived fine.
I’d do that again in a heartbeat.