I've been an eBayer for six years now and have never encountered this before. I want to be polite without being pushy and I hope someone has advice!

I won an auction for an item recently. It's something a little rare and I was thrilled to get it. I paid immediately and thought that was that.
With everyone I've bought from in the past six years, I've received e-mail acknowledgment of my purchase and some shipping information within 24 hours of the sale, at least. I waited three days with this one. Still nothing. I sent the seller a polite message, saying that I just wanted to check that everything was OK with the transaction, and did she know when she'd be sending it?
That was three days ago. Still nothing. The seller doesn't have a perfect feedback record, but a good enough one with lots of sales that she fell well within the range I'd consider acceptable. I suppose she might have already shipped it and is just ignoring me, but the lack of communication is really bugging me. This is a slightly rare item and I've had other chances to chase it down over the past week, but declined because I'd thought I'd bought one! (And the longer I wait, the harder it will be to find ...)
Here's when some of my confusion comes in: I browsed the eBay forums trying to figure out what to do. They seem rather seller-centric. In a few cases like mine, many people agreed that a message (even a polite one) so soon was "pushy" and that "communication is optional."

(And also that it's poor form to leave a bad communication rating if I do get the item, even if the seller ignores me all along.)
Was I pushy? What do you think my next step should be? I was thinking another polite message if i don't hear anything by tomorrow, then take it to eBay if I don't hear with 3-4 days after that ... but now, I don't know.