The case dimensions are very close and you can resize the 404 in the 11.2x72 dies and a short trim. That's the easy part.
Now you have to chuck the 404 case in a lathe and turn the case rim down to the rebated rim size of the 11.2, then have to cut a new extractor groove to match the correct one in the 11.2. So until they get a run of the correct brass into suppliers you at least should be able to make some. Since the Ultra mag cases also use a 404 as the parent case in theory you should also be able to make brass from them.
Bullets you can find Hawk, woodleighs or cast bullets. There might be a few others out there. can also swage 45cal down.