Hello maybe an approach like this
**broken link removed**
is better and cheaper. In fact I would use a tiny from atmel because development and programming tools, if I am not wrong are reused... I think that if many chips are feeded the clock output should be buffered.. if internal clock tolerance of the uC is not enough, external and comercially available crystal maybe used and its frequency arbitrary divided...
Given that this approach uses a uC, you can take advantage of this adding more task and functionalities to it like external watchdog, reset circuit, power supply monitor, etc...
hope it helps...
peyro