5.0 GT Fuel Grommet

1994 Mustang GT, 64,000 miles, 5spd, 5.0L
Hi, the fuel filler-neck grommet is leaking on my Mustang. I know the problem, but I cannot find a grommet and it's beginning to look impossible. I have spent weeks trying to locate a grommet and/or donor but no luck. I would greatly appreciate any help such as what vehicles may have a compatible grommet etc. Or any easy fix-it advice.
Thank you,
J