You might want to consider "Tray Cable" for your longer runs. (Example-
http://www.delcowireus.com/tray_cable.php ) It is very effective except in cold weather, which does not sound like a factor for you. Its UL approved at 600
volts and comes in 14, 12, and 10
AWG Depending on the gauge, they are available with up to 60 conductors (#14, nineteen conductors for the #10) The casing is pretty tough and even the rock and roll roadies never cut one up on me. (Its even rated for direct burial.) Where you need cold flexibility, you could use SDN (Example-
http://www.calvert-wire.com/show_product.php?id=235 )
In all cases, it sounds like buying your own is the best bet.