That's a tough one --
I know that Doba.com has Warhammer products listed, but you would need to pay to sign up with Doba to access them (although they do offer a 7-day free trial). In addition, I found a supplier on Shopster.com who has Warhammer products as well, and it's free to set up an account on Shopster to contact this supplier (Games & Games).
Barring those options, you could go to Google and type in "warhammer wholesale" or "warhammer dropshipper" and see what comes up.
I just did that, and I found a website that looks like it could be very promising for you:
I hope that helps!