Reply by CaptainKlutz

Lots of OEM make 1HP wall mount DC that use similar bag style. Grizzly G1163, ShopFox W1826, and Rockler sells Dust Right 1HP too. Can get replacement bags for all these machines. Can even buy cartridge filter upgrades, assuming your output port has enough clearance, or you add extension.
Powertech sells a universal 3um filter bag that will be better than standard 30um used standard with some DC.

Penn State offers a 1um filter bag.

There are many folks like Standard Filter, that stock 55 gal drum head filter bags too. Cincinnati Fan still makes the 55 gal drum head DC and accessories. Not as easy to find online, and usually have to call to get right PN.

Best Luck.

-- If it wasn't for bad luck, I wouldn't have no luck at all, Doom, despair, agony on me… - Albert King - Born Under a Bad Sign released 1967