Shutdown instead of sleep MAC with energy savers or screen savers?

Hi,

(1) Is there a function—or third-party app, willing to pay—that allows me to have my MAC shutdown (instead of going to sleep) when the energy savers (or the screen savers) would usuall be triggered?

(What I want to do is to make sure my MAC shuts down after it idle for say 3h: there are a lot of electrical devices connected to the MAC and they start up and shut down automatically with the MAC via an USB connected powerboard. This is usually great, as I have nothing to switch on of off manually, but if I forget to power down the MAC going to work or for a weekend trip, the amp, for example, gets really hot. That should not be. Sleep does not help, the powerboard still sees it as on as the USB port still has power.)

(2) Relate to (1): Can I set this up to "force shutdown" instead of being held up by applictions ("iTunes is currenlty downloading podcast, do you really want to quit" > YES of course, but I am not there to click yes).

Thank you for any hint,

Daniel