The cable isn't an issue so much as the connector. If you have all that daisy chained together with 4-pin molex plugs you'll have a big problem. There's too much resistance in the plugs and you can easily discover that by touching the first one in the chain while under load... it will be very hot.
6 fans is the max for one connector, and not chained together but split with a device like this:http://www.frozencpu.com/products/1024/bus-81/SunBeam_Multi_Fan_Power_Port_MFPP.html?tl=g47c121s424
I think you are using that aren't you?
I would feel fine about one cable per list, just not one molex
You aren't going to draw too much power from the rail, the PSU will protect you there. But you CAN draw too much power through a single molex connection.
Scroll down and look at the right hand box on this page:http://en.wikipedia.org/wiki/Molex_connector
The max draw through that type of connection is 11A.