Re: 4 inch Drum heads - Can I cut one or make one?
I think it would be a hassle to cut and refit a drumhead. Those come from the factory crimped or glued in aluminum collar.
A few options for you. I have heard of people re-heading a hand drum with an X-ray, apparently they're similar to a drumhead. You could also make one out or rawhide.
You could use a 6" drumhead and just use spacers under the lugs, the bearing edge will be exposed though.
Last option would be to contact Remo and have them make you a 4" drumhead.