That’s probably true. Indeed, for Photoshopping a integrated digitizer is the best you can have, but I have yet to see extremely powerful laptops with one. What does the OP want to do except for PS with such a machine? Play?
If it’s indeed for PS mainly, I’d look into the offerings of the well known business notebook brands. Fujitsu has as far as I am aware of by far the longest experience with Convertible & Slate Digitizer-equipped laptops. The Lifebook T900 seems to have the most powerful processor available (up to Dual Core i7 2.66Ghz), but just the totally non-Games-capable chipset graphics of the Intel QM57 chipset.
Anything more powerful will not have a digitizer, as far as I am aware of. If you want top notch performance & graphics, probably some of the gaming notebooks that are more or less desktop PC size and weight, though, might be an option. No integrated digitizer, though.
But of course, besides Fujitsu in the recent years a lot of other companies are slowly jumping onto the Convertible trend… like for example (quoting only the ones known for good quality business notebooks):
Lenovo (ex IBM): X200, X201 (similar specs than above)
HP: EliteBook 2740p (similar specs)
DELL: Latitude XT2 (lower specs)
The only thing I can say from my experience in the computer business (development actually): If you want something reasonably reliable, your best chances are with the business lines of the top brands, see above. Everything else (like consumer laptops) hit or miss… you can get lucky and have a well engineered system, or you are (more likely) unlucky and have systems with severe design issues. If you are very lucky, those design issues don’t affect you, though.
Unfortunately, with consumer notebooks, even by spending more you can not increase the chance of getting a good product - you just buy more features or performance.
Either way: Good luck in choosing a laptop. I don’t want to give any advice on brands, because in my experience all brands have good as well as bad products. Like most modern computer products, it totally depends on the quality of the design team that is in charge of the product…