no man i'm fully wired!! you sure are hard to find

YES -- if you're careful about channel assignments any 1/4" phone plug-style coaxial cable can be replaced with a wireless transmitter/receiver pair.

Why would you want to do that?

It's an extremely effective way to eliminate the noise caused by ground currents carried in the cable shield, and because the transmitter isn't moving around the room, antenna field related dropouts are pretty much eliminated too (the area of coverage is determined by the relative positions of the Tx and Rx antennas and (here's the kicker) any other metallic object that resembles an antenna).

What about the signal levels?

Wireless systems are designed to send the same audio signal level to the amp that is generated by the instrument, which is quite a bit lower than the Line Level signal found at the post-preamp Effects Send, so if you are using a wireless system in your effect loop be sure to test for distortion at high volume levels. Most wireless systems can handle the higher signal levels, but you may have to make some minor adjustments to output and input levels to keep the signal linear. 

So how do I know this works?

I use an old UHF Nady unit with the instrument transmitter plugged into the Preamp Out on my Fender Deluxe 90 and the receiver plugged into the line input for my outboard equipment rack, and another clearance bin Nady rig between the outboard gear and the Deluxe 90's Power Amp In. It not only completely eliminated about 80% of the noise caused by the crappy wiring on most tavern stages, I can set my amp up as far behind me as the stage will allow and put the outboard gear rack where I can reach it easily (I'm always fiddling with the 32-band EQ and  the compressor settings). It also lets me leave some 50 feet of cable in the trunk instead of underfoot.

The Down Side:

Two more batteries to forget to replace until right in the middle of a particularly hot solo. 

To sum up, give it a try -- you aren't breaking any Laws of Technology and it's a good way to enhance your Carbon Footprint by not throwing away those cheap Karaoke wireless rigs you (if you're like me) can't help fishing out of the clearance bins --

Rock On!

OldRobP