The old style grill cloth is like the holy grail, the subject comes up every so often but never gets fruitful results. As far as I know there is nowhere to get it new, I think the only chance is if someone is hoarding some NOS either intentionally or otherwise.
I spoke with Wendell Fabrics (who manufacture Mellotone) about re manufacturing some, and was told that due to EPA regulations that old style cloth can no longer be produced in the US; some chemical or material used in it's production is banned.
He also told me that I wasn't the first inquiry about it!