Actually guys, in the powered enclosure world that we're living in, it's become very common. Everyone is running power and audio together anyway, it's just something that's evolving into something more convenient.
Imagine guys running stage monitors with powered boxes having to run two individual cables to each enclosure instead of just one. Having it in one jacket isn't adding much more susceptibility than what we already have with an XLR + Power line run parallel on the floor for 75'. You have to remember, the signal cable is line level, not mic lines.
In our situation, we have several powered Meyer enclosures that already have signal and power run parallel for distances between 25' to up to 100'.
One example of what I'm talking about:
http://www.samedaymusic.com/product--CBIMTPA1XEI
Since I posted this, I've found out that Whirlwind and others are selling the cable bulk as well in a variety of configs.