Good idea, yarnrainbow! and of course, I'd add that it's not kosher to approach people about buying their yarn if it isn't specfically in their FOR SALE or TRADE folder.
Raverly software is getting better at posting a little note by people's yarn stash about NOT FOR SALE or FOR SALE.
It's best to respect the knitter who owns the yarn. People can be very prickly these days.
The thing that irks me A LITTLE is when people message me about "will you sell me only 5 of them? I only need 5 for my project" when I've listed 12 for sale....a sweater's worth.
So I respond "if I sell you five only...I'll be in your predicament...not enough yarn to finish my project...if the yarn doesn't sell, I'll knit a sweater with it..."
Anyway, just sayin....
Good luck with your search! I've been in your shoes!