I notice that there are a lot of rebates and "instant savings" at B&H which are good through January 7th. Is that B&H or Canon offering these promotions?
Is there a list which shows all of the lenses and equipment for which there are rebates and "instant savings" during this period?
I suppose it's not a good time to sell my EF-S 10-22mm wide-angle zoom. I should probably wait until after the 7th.
Usually they are offered to the seller and some sellers pass them on to the customers. You'll find a lot of bitter commentary on the subject.
Usually this rebate period coincides with a price increase from Canon, so when the lower price inventory sells out, the price goes up and you get MORE vitriolic commentary concerning vendors "keeping" the rebate.
So you're left deciding whether you'd rather sell your lens now while people are shopping, or wait till January when perhaps they've bought a new one.
I published a list of eligible products at my blog. It is a Canon promotion, though individual dealers are sometimes adding their own additional savings (as B&H recently did with the 16-35 for a couple days.)
Canon does promotions like this from time to time, but this one includes more and better lenses than I recall seeing in other recent promotions, along with a bunch of Speedlites.