[TowerTalk] 75 or 70 Ohm twinlead or ladderline cable - does it exist?

[Rick Stealey]

So it looks like we have an alternative to coax or open wire line to feed a dipole for example.
If I took, say, #14 stranded, and twisted it, it would be a good match for a center fed dipole, low loss and not a high SWR so it would present a reasonable impedance on one band, at the output of a tuner or transmitter.
Sounds good.  However, the savings over coax isn't REAL great.  $50 for 500 ft of THHN $14 at Home Depot, means 20 cents a foot for a pair.  Maybe the weight would be less than RG8X.  
What about the power handling ability?  Would it take maximum legal power (1500 watts in USA, before someone reminds me it's lower in G-land!).
What about using this type of line for a long run to a beam?  It is obvioulsy VERY flexible.  Would the feedline radiation/reception be good enough that it wouldn't upset the yagi pattern?

Rick  K2XT