Live anywhere near Melbourne, Victoria, Australia? Checkout the local LAN gaming scene at Shafted LAN.
I did a fix for VIS in 1997 which gave you a speed up of 33% to 50%. I also did a patch which gives you another 5% to 10% speedup.
For HalfLife - Speed your map VIS tool by 45%. Zoner has put these speedups into Zoner's Half-Life Compile Tools as of version 2.3.
For Quake - Speed your map VIS tool by 40%. Here is the original RVIS1, done while I was at TeamFortress Software.