I live in BC, Canada, and researched Yorkies for 3-4 months before finding Missy. The prices here are outrageous! I got a steal of a deal when I bought Missy for $950 from a backyard breeder with NO papers. I realized that I was taking a risk buying her, but hey...what can you do when you fall in love. I also got Missy too early at 7 weeks, 3 days of age...but the breeders vet OK'ed the puppies to go, so off they went. I wasn't letting anyone else take my Missy home. I snatched her up! We had problems with low blood sugar, it was scarey. But we worked through all that, and now she's doing great.
I think that you just have to follow your gut instinct in these types of situations. Everything felt right with Missy, so I just went for it. I guess we'll see what the future holds.