do a search on clutch slave cylinders. evoluzione, stm and yoyodyne make units with a larger bore. larger bore -> more fluid displaced -> less lever effort but longer lever throw.
personally, i haven't really had much issue with it. felt a bit heavy at first but you get used to it.
Not to sound like a jerk, and I know this will come out wrong but a hand grip exerciser is cheaper then a new cylinder and you'll get stronger in the process. Its all a matter of getting used to it. Your hand will just strenghthen over time. With all due respect. I had the same issue when I started riding.
aye, my hand ached for about 2 weeks of stop start city riding. dont really notice now, the buggers at the local duc placed laughed at me when i asked about the heavy clutch, they said i should learn to filter through traffic :