There are a great many display technologies available if you wish to make a digital clock. Many hackers seem to have a penchant for the glowier fare from the Eastern side of the Berlin Wall.

Your in luck! Cheese @ Bit-Tech has come up with a neat 'piggy-back' device that will allow each of your GPO's to support 32W @ 12V. Click here to check it out. Why did you go for a PCB based approach ...