I'm guessing from your email that the customer wants to use 4 line non-ksu phones. Sure, it's his money and his business. If it doesn't work well, then it's his problem.
I would bring the 16 Cat 5 voice cables to 3 66 blocks mounted next to the feed coming in from the cable company. Cut the cables down on one side of the blocks and then loop the 4 lines to each of the cables, terminating the cross connects on the opposite side of the block. Use bridging clips to establish a connection. (This will help you to troubleshoot in the event you've got a bad set that screws up the whole shebang.)
Now you're all set for when the phones don't work. Doing it this way, it should be easy enough to have a telephone vendor install a real phone system and connect it up properly.
Sam
