Don't wire funds
I'll give you some free advice coming from someone (myself) who sold the classic and touch models in bulk to the UK from September-December; tread very carefully. I don't know if you're receiving low or high offers, but ask them how many packages they've shipped out in the past 3 months for iPods. If they say hundreds, ask for tracking #s. I doubt they will reply. I've always provided tracking #s and can backup my statements.
For USA customers, I've always accepted a credit card funded transaction - are these other "wholesalers" requiring wire transfer? Never wire money on a first time transaction (and I'll always pay the 2% surcharge to pay via credit anyway - I get 2% cash back on my card anyway).