It looks like Retina display is coming to the Macs. When?
it's anyone's guess but Arstechnica has a good detailed section on it within their Lion review article. It's definitely must read on both accounts.
Again, the question is when will this happen? I think Apple is likely trying to leverage this technology as soon as it can. It'll be inconceivable that its competitors can move fast enough. After all, Apple is probably going to update the iPad with the Retina display sooner rather than later. This could mean that the economy of scales of the iPad screens can also help Apple absorb any increase in display prices for the Macs in the future.
That said, when Apple increase the iPhone 4 due to it having the updated Retina display over the 3GS, it could be promising that the Macbooks, iMac, and the Cinema displays get Retina upgrades without much if a price increase if any. I would not be shocked if Apple does provide the current LCD display with the Retina option in future Mac upgrades.
Such a move could potentially bring the new Retina displays faster to the market. Let the customer chose if they want to pay a premium for better displays. Therefore, I disagree with Arstechnica's assessment that we will have to wait quite a bit longer for it.