I searched around and haven't found any source, but it's likely that somewhere, some office supply Mfg. would have these?

Found a coin dealer who offers a variety of empty Dansco holders, that I believe use the same pages. They aren't the vinyl cover type, and have a flat spine. $7.96 each.

http://www.kaymariecoin.com/index.php?main_page=index&cPath=1_7_10

The name Gardmaster came up as an apparent replacement for the Harco Gardmaster books and pages.

Some of my empty pages that I bought at a coin show are labeled "Edgar Marcus & Co." no luck with any screwpost binders.

I can find pages, I've never found the albums except Dansco.