Locating wires "buried" in my walls

I purchased a home a bit ago and have made good progress tracing most of the wiring (multiple cat5 runs and a single coax line in each room, all terminating in roughly the same spot in the basement) that I can acces without cutting holes in the walls. None of it was diagrammed or labelled and almost none were terminated with jacks and faceplates, but that has been corrected.

I have a bit of trouble with the whole house audio as it has not only been totally undocumented and unlabelled (with the exception of a single "basement" label written with a Sharpie on one wire) but also they failed to provide any direction (via blank faceplates etc) where the wires may run and terminate, except for 1 pair of speakers with a volume controller each in the MBR and the living room, and 1 pair of bare audio wires with a volume controller each in the porch and garage. There is also a single cat5 into the MBR to a Niles IR faceplate.

In the audio area, I have a few more wires I'd like to investigate:
multiple cat5 wires that don't seem to terminate in my basement as I expected they would
2 sets of speaker pair + cat5 wires (taped together; audio + control?) which must run somewhere, but I don't know where [one of these has the label "basement"]

Short of cutting holes in all my walls trying to find these wires, is there a product which could help me trace things out? Ideally it would be like a fox and hound and I could walk around the house running it along the walls, and it would give me a PING or something.

I am not opposed to paying an A/V pro/firm to help with this, but I'm not paying $1k just to find a couple wires in my walls either.

Thanks!

I have already located and diagrammed etc all wires that have both ends exposed somewhere (such as behind a faceplate etc). That is no issue and it has been done 100% with my existing tools.

Now I have multiple sets of wires in the distribution area which simply disappear into the walls, and never appear anywhere. If I had a clue where the ends were, I would cut holes in the drywall and put in a proper box etc. This is exactly the challenge.

Does there exist a product which can help me locate these wires in the walls, for which I have full access to one end but no clue where the other end may be?? There is an attic but it will not be helpful as this is a 3-story home and the distribution area is in the main floor, and the areas where the wires seem to be running is 100% blocked with drywall or the floor of a level or the ceiling of another.

I found mention of a product which somehow converts the wires in the walls into basically a radio transmitter, like a super Fox and Hound based on RF. Does anyone know about such a product? I'd happily buy one used, use it, then sell it again (or rent it if possible) for this task alone. I may even find a couple friends who could use it to further defray the cost.

edit: I will add that I have Gardner Bender ET64220 Wire Tracker from HD that I've been using with good success for the exposed wires. And it works a little bit through the drywall, but only if the wire is close enough to the drywall and only if you know exactly where it is located behind the drywall. In other words, it does me almost no good at all for my current predicament. If I knew the Fluke PRO 3000 or another similar product would generate a much stronger signal which would work from say 10-12 inches away then I might be inclined to try it, but I don't want to buy it and open it up etc just to realize it works essentially identical to the GB I already have.
Edited by wfay - 9/4/12 at 1:01pm