Most RENIX harness connectors are regular ol' GM/Delco Weatherpacks, so your local should be able to do those for you. The Knock sensor is a Bosch fuel injector connector, and the IAC is some sort of fairly standard GM thingie that I just haven't looked up yet.
What are you trying to do? Have you gone to groups.yahoo.com/group/RENIXPower yet? It's a group I started for RENIX information and experimentation - I have a compleat system waiting for me to set it up and start playing...
Anyhow, you should be able to find most of those connectors with a minimum of difficulty - the only real ache is likely to be the IAC - but it's out there (I've bought one before, I just don't remember where.)
5-90