When the previous hardware revision launched here, the DSi clocked in at $100 more than the DS Lite. Of course, the DSi did have some new features to justify the price hike, but regardless Nintendo did effectively increase the system's price by 50%.
The DSi XL doesn't have any new features over the DSi, but it is a lot larger, as you can see. Surely it'd be more expensive again?
Nope. It's the same price as the regular DSi: $299.95.
It's possible Nintendo could adjust the DSi and DS Lite prices once the XL actually launches - and I've asked them that very question. We'll see if they respond. Right now, though, I'm pleasantly surprised they didn't seize the opportunity to raise the system's price once again.