I couldn't find one on Racing Planet USA site, but I found one on their DE site.
Maybe hit 'em up and see if they can get you one or two for not insane shipping.
Beyond that I'd haunt ebay a bit, & probably end up buying a couple from the UK or something (saves on shipping to buy more than one.)
If you want the cloth filter route the KN filter KY-2911 should work, & could cost about two of the OEMs.
Depending on how often you re-oil it you'd come out ahead.
https://www.amazon.com/KY-2911-Replacement-Air-Filter/dp/B01M7PDM96https://www.knfilters.com/search/applications.aspx?prod=KY-2911 - Note how extensive the cross reference is on this...If nothing else that might help with an ebay search.
I have a fabric filter for my B650, but I bought that before the aftermarket finally came through with an inexpensive paper filter for them. I'd have gone with that if I didn't already have the fabric one. They filter a bit better.
You final choice would be the cheapest, but take the most messing around.
Take your old filter to a FLAPS & do something like this.
http://symforum.com/index.php?topic=2436.msg33815#msg33815I've seen that one with a car filter donor as shown, furnace filters, & sheet foam filter material like this
https://www.amazon.com/Uni-Filter-65-PPI-Green-Fine/dp/B000ONZT5E.I've done the foam on my prior burger, but it went with it. It's about the same filtering as a cloth one so I just bought a cloth one for my current one.
No idea what's best for your application but you get the idea.
Lots of folks on the BUSA forum did this & may well still do it. Folks do this with their HD200s as well since the filters were tough to get for some time & the dealer one is insanely spendy. (Racing planet has an aftermarket one cheap if ya order a few.)
If you want to be extra fancy get some foam filter material (you can buy it by the sheet from a lot of motorcycle/power sports out fits), & use your frame as noted above with that. That'd give you the equiv of the fabric filter for about the cost of a UK one use filter.