Reply to "Clutch Slave Cylinder - Alternatives to the OE Style Part??"

Rob, the only aftermarket slave cylinder I’m aware of is the “long throw” slave cylinder. It has a slightly smaller bore than OEM, to give a bit more travel (albeit with a heavier pedal). This was a Pantera East item but they are no longer in business, so I’m not aware of the current source. I’d try Dennis Quella or IPSCO (Mark Johnson).
The other aftermarket option is a hydraulic throwout bearing, such as the one McLeod makes, however, it is far from a bolt-in. To do it correctly requires some fabrication and non-trivial measurements and setup. TBS, once it’s installed and working properly, they can be very reliable and give lower pedal pressure with great clutch “feel”.  Get it wrong though, and you’ll get lots of practice pulling your transaxle! Virtually all modern vehicles with manual transmissions use this style of slave cylinder/throwout bearing.