Ok, If the fork components are becoming rare then in my personal opinion its time to swap to the internal slave cylinder. It actually a very simple but time consuming swap. GM went to the Internal slave cylinder in 1998 when the NV4500 MT8 was changed to the MW3. Differences are the slave cylinder and clutch change. Inside the gear ratios changed. you now have a 5.56 first and reverse gears. Now first and reverse are now synchronized. Other then that, they are the same. Hell I have a 2004 LQ4 bell housing attached to my 1993 5.7. Are they different? Yes and No. They kept the same 1958 bolt pattern but added an extra one at the top.
For you to swap to the internal slave, you need: Hydraulic line for the new slave. This one is shorter and flexible because instead of being on the passenger side it will now connect to the drivers side. Slave Cylinder with throw out bearing. A 1998 one ton clutch. You can use the original flywheel that came with your truck.
Remove the transmission. Remove clutch. Note: you cannot use the old clutch. the new one has a thinner pressure plate. Remove flywheel. Note: If it can be turned and stay within specs then that is $35 at the local machine shop. Remove pilot bearing/bushing. Note: This is always good practice. There are pullers for this that you can rent from your local Autozone or Orilliy's. Remove fluid from the Master cylinder. Note: This is important for the next step. Also, if you don't want brake fluid to eat your paint on the fender then have a catcher and a quick clean-up ready. Remove the pin that holds the hydraulic hose to the master cylinder. This is where catching fluid is important. Connect the new hose and replace the pin. Route the hose in a place where the exhaust or anything else will effect the hose. Install new polite bearing/bushing in the back of the crank. Install flywheel and torque to specs. Please do not use German torque specs. Install disc and pressure plate. Use alignment tool to alien disc by centering and pushing the tool up as far as you can. Install slave cylinder to the transmission. Stab the transmission. Torque bell housing bolts to specs. Install the rest of the components, cross member, shifter, transfer case (if 4x4) and drive shaft. replace any fluid lost in the tranny.
http://www.advanceadapters.com/tech-vault/2-nv4500-transmission-identification/
Internal slave cylinder were first seen in 1996. 1995 had the 5.61 1st gear with external slave cylinder.