I've worked quite alot with different types of data cables. I can't really see why more people don't go for fibre cables. With copper ethernet you can choose stranded or single core, but there is some difference in signal quality over longer distances, as one would see using for example a fluke meeter.
There are lot of different solutions for fibre, also this is what the army prefers to use. So you're guarantied to find some hardened products. Fibre also has the advantage of not picking up interference from power cables, so you can run them along side the power cables going from foh to stage or power distro. Using fibre you've also optoisolated the sound equipment foh from everything else at the stage.
I know blackbox makes a hardened fibre cable on a reel, we used 2 of them to link 2 data centers togheter over the road from each other while moving from one side of the road to another.
http://blackbox.com/Catalog/Detail.aspx?cid=1286,1623,1640&a mp;mid=4948 might be interesting for some of you.