Welcome to the forum LBS.
I'm 6'2" and I've always been comfortable in my Crossfire. It may take a couple minutes to find the "sweet spot" with the power seats, but don't get discouraged, it's in there.
The "base" cars come with manual seats, and sometimes they make it easier to find "the sweet spot" because they offer less positions to choose from. They are very comfortable "cloth" versions of the SLK seats, and I felt as though I actually had a little more head room in the "Base" car thanks to the seat.
I've owned 3 Corvette C3's and you're right, the interiors are similar in size. (I never thought about that before). Too bad the Crossfire never offered a tilt steering wheel. That being said, I've always been satisfied with it's position, and like the Vette, it's telescopic.
Good hunting, and take your time finding just the right one. These really are fun cars to drive, and be prepared to get very involved with it. (Most owners are.