When do Apple Authorized retailers get refreshed? How long is it usually between when Apple releases a refreshed product and when authorized retailers like Best Buy and Target get the updates?

I feel like when the last iPod refresh happened it took about a month before Target got the new ones. I ask because my wife is a Target employee and I'm debating how much I want to wait to get the new iPad vs saving 15%.

UPDATE 3/4/11

My wife talked to the analyst, and she said Apple doesn't work with vendors before a release, and it's up to the specific vendor to scramble for orders once the product is announce.  Bestbuy and Walmart will be getting it on the first day.
Authorized retailers can order the new units from Apple more or less at the same time the Apple Stores get the new stuff. But while Apple Stores get the new stuff out on the sales floor at launch, the other retailers, for whom Apple gear is a small part of their business, may take longer to get the new stuff shipped from Apple, into their inventory systems, go through their internal distribution, and get it on their floors.