Where to find a truss rod nut?

Thanks to all who gave me advice on my fretboard removal/replacement questions!

Now, the previous owner of the bass that I'm working on had done a pretty good job of rounding out the truss rod nut so an allen wrench doesn't properly fit. The problem is that the rod is metric (M6 x 1.0) and all the places online that I've checked (Warmoth, Stew Mac, LMII) only sell standard nuts. Does Allparts carry anything like this? Any other ideas?

For what it's worth, the bass is a discontinued Ibanez... has anyone tried dealing with getting parts from them?

Thanks,

Steve