Im working on a 1/35 Academy AH-1W and even the Cobra Company resin cockpit doesnt have some major wiring and "plumbing" going on in the cockpit itself and in the rear bulkhead that I need to build. So what do you guys use for wires and electrical conduits, etc. in 1/35 scale?

a great source for various size wire and 'plumbing' is a TV cable section. You get the main thick middle and some thin insulation wire.
Another source is the inside wire from a (Spare) computer mouse. You can use with or without interior insulation. There are three or four thicknesses.
Other sources are car wiring harnesses, old sterio wires, etc.

Slodder I love you man!! I dont know why I didnt think of my old headphones that were lying right in front of me. Now I can really detail my cockpit! Thanks a bunch amigo.

Another option is different diameters of electrical solder. It issoft enough to be bent to any shape and will hold that shape easily.

I started to use some copper solder for a few things but for most it was too thick. The only thing I want to do is not to spend any money Arty so Slodders choices come in very handy. Thanks anyway bubba.

have a look around and see if you can find some telephone wire lying around this is quite fine and if it still has it's insulating sheath on you cut it ten pull it off leaving a steapped effect for pipe work/cabling ect also dont forget fishing wire/solder comes in various gauges

You might also find that old electronics toys or gadgets are a good source for wires and junk. Slightly off topic but not by much... if you consider motorizing the rotors an easy way to get the same effect on the tail rotor is to use an old cell phone buzzer motor. They are very small and would probably fit in the Cobra tail. Hope this helps!
Kyle