Well the 1995 and earlier HP cranks had the needle bearing upper which we call the "small bearing", in 1996 they went to the "big bearing" which is the big ball bearing which is what they kept after that.
On the early Big bearing cranks, say 1996 thru mid year 1998, the bearing area on the upper was still the diameter used on the small bearing cranks, which is incorrect for the inner diameter of the ball bearing. So what they did was put a sleeve on the crank to make up for the difference. The problem is, the sleeve isn't robust enough to maintain its size. So after time, the upper bearing will lose its press fit. Lots of times when you take the crank out the bearing will just fall off.
I've seen people try many ways to regain the press on the bearing. But what you can do is take the sleeve off the crank and then use it as a small bearing crank. Mercury even made an adaptor to use this small bearing crank in the big bearing block.
The third variation you must be thinking of is the promax crank with the captive large flat roller bearing at the top. That is just a fishing motor crank.
