Looks like a sale on L lenses might be on the horizon after all. We’re seeing a massive price drop at Best Buy with savings from $100 to $300 off L lenses, which undoes the price increase seen last month (and in some cases, goes even lower).
UPDATE: It looks like Canon just started a mail-in rebate for this time period, and Best Buy may have accidentally applied the prices as if it were an instant rebate. So this is a price mistake that might be fixed shortly. This might be an opportunity to see if you can double-dip the rebate — buy at the lower price — if Best Buy will fill your order — and still get the rebate. Example: buy 24-70 II for $1999, mail-in for the $300 rebate, net price: $1699.
UPDATE 2: Despite comments to the contrary, this deal is still live as of 6:30 PM ET. Best Buy is still showing the lower prices during checkout. Best Buy is an authorized dealer and thus the mail-in rebate should be valid for them. If you read the fine print on the Canon rebate form there aren’t any clauses that would exclude Best Buy or invalidate the rebate claim. (It’s Canon, not Best Buy, that is paying the rebate and they probably don’t care what the purchase price was.) That being said, please do try this at your own risk. 🙂
UPDATE 3: 11 PM ET: 24-70 II out of stock.
UPDATE 4: I (and several others) called the Canon Rebates hotline (1-866-668-9861) and asked about the Best Buy eligibility. According to the agent I spoke to, the list was not published yet but she felt that Best Buy would not be a valid retailer for this rebate (even though they are an authorized dealer). Shame on Canon for not being transparent about this on their mail-in rebate form.
UPDATE 5: The list is published and I’m getting conflicting information: according to the official rebate site, BEST BUY COMPANY INC. is on the list of participating retailers for this rebate. Here’s a link to the list. I’ve also included a screenshot just in case:

I called them again and they said the list was the official list and will not be changed, and if Best Buy is on the list, they are eligible. I recommend calling yourself to confirm: 1-866-668-9861.
Here are some of the drops we saw: