I've found some will especially if you detail a little bit of what you've done in a technical fashion, so you sound like you know what you're talking about
Blackstar are excellent
I got the schematic for the HT metal pedal and then asked where I could get the pots and they sent me a bag of all the values for free
I did find the pot type but not the correct value on eBay at a ridiculous price of £17 each!
Digitech / Harman eventually must have got fed up with my emails and sent me the DL8 Delay schematic with nothing in writing just a blank email with the schem attached!
I was surprised it didn't say now go away.....please
Dunlop absolutely no chance even for out of production pedals but worth contacting for local dealers
I just got an email from my local dealer offering me a salvaged but mint C500K 9mm pot and tactile switch for nothing for this damn 95Q I'm still trying to fix
I've also had a little success with Zvex finding out what type of switches are used in pedals I'm trying to suss out ie on off on etc
So I think if you speak their language and say things like I've checked op amp voltages and I'm getting correct bias, I've looked at it on my oscope etc they're sometimes very helpful