What gun is it? Another option may be to modify an existing mold to work...
It's an STI Guardian. The dust cover is longer (gov't length) but on a 4" gun. The other oddity is that the tri top leaves a little extra meat on the top so it's excessively tight in holsters, even when we block the mold for the dust cover. (We've done that, and it worked well)
@muzzleblast... built me an OWB that is great- he blocked the dust cover with a precisely cut piece of leather to fill out the mold to match. Then I used multiple baggies and some well placed masking tape to stretch it out to accommodate the slide difference. It was a lot of work to stretch it enough and right.
At the moment, I'm specifically after a Sparks Summer Special II for this gun. I've send pics and measurements to them and they can accommodate the dust cover but the slide is a hanging point.
Since this is a
forever gun for me, I don't mind spending a few hundred bucks if needed, to have a mold made. I'm also considering a 2nd custom job on another Guardian base gun, so the mold would be used a number of times.
Depending on how "oddball" your gun is, many holster makers use "Blue Guns" to make their holsters.
Unfortunately they don't make this one in a blue or other dummy gun. (that I've found yet)