Todd,if you really are concerned,we had a post about buying the parts from Radio Shack with the exact part numbers for a couple dollars and however much cable you wished to extend.They had done up to 1,000 ft-I believe.
Maybe a Taylor?
Smokin' may be able to find the old post on here,or maybe I can find my hard copy.
I know that one large load ruined can justify about any expense-but I think you'll find that fooling around with the batteries,poor response,etc will be enough aggravation that you won't mess with the Maverick,or a comparable unit.I've also gotten a false feeling of security using them.
Bill[Dixie Chicks] loves gadgets and had an English send and receive unit that actually would work.His email is maybe around on the CS forums?
I carry a Maverick in the cook kit and I loan it out occasionally,but never use it.
On all our cookers over a bunch of yrs,and all the folks I've cooked with,I really can't remember a single time I've missed a wireless.
Of course,I do tend to walk by the cookers every few hrs,just to satisfy myself.
Fast Eddy taught many of us,even on long distance/expensive contest trips to get our big meats running right on the FEC and go to the motel ,until time to come back and get the ribs ready to go on.
Now,I plug a Taylor[ or any box store unit] into my big meats when I figure I'm within a couple,or three hrs of needing to check doneness with an instaread.
Seems like any CS cookers,once I've figured out the hot/cool spots and the approximate timing kinda take care of themselves.
Just my experiences,but hope this helps a little.