Need some recomendations on Electrical Testers

Hi guys,
I know this is a question that many of us with older homes and buildings can relate too so I hope you guys can help.
I am working in an old theater that was built over 50 years ago which has gone through many changes over the years. Like many old buildings theirs allot of wires coming in and out of panels that have not been used in some time, nor does any one know what they were used for much less where they go in the building. Also like many old building back when they were built no one believed in creating blueprints of the wiring, or at least those over the years those blueprints have disappeared if they were even created.
Now I know there is a vast amount of electrical testers on the market to help test a wide range of things.
Is there a 2 part tester in which I can connect a alligator clip on one end of a wire some where in the building, and using the second part of the tester, "SNIFF" our the line so I can see where it goes in the building.
I know this seems like " A needle in the Hay Stack" type of question, but is there any tools out there that can help.
Any thoughts is greatly appreciated,
Thanks,
soundguy_99

http://cableorganizer.com/triplett/t...-hound2kit.htm

Thanks thatguy,
I have looked into it, and a few other testers,
Looks like they are very handy for a wide range of things,
Thanks for the link,
soundguy

You're welcome.
Depending on the layout, there are more labor-intensive ways of doping out the wiring just using a D cell and a lamp. It's tedious but it also works.

Tone generators do not always have a great range, so if the wire is too deep in the wall it will not trace its path, and if it is conduit, which should be the case for a theater, no matter when it was constructed, then they do not work at all. except at the end of the wire where it enters the junction box.