Really? You want a big clock? How about this idea: build an appropriate-sized square tower. At the top of the tower, on all four sides, mount JumboTrons. In a small computer, add the appropriate clock app. Use a video distribution amp to feed the video to all four JumboTrons. You now have a clock that can be read for miles.
Want it to chime? Easy enough to add outdoor speakers, a suitable 70 volt audio amp, and a chime generator. If you're smart and use Linux, you can use cron(1), play(1), and audio files to make the appropriate noises at the appropriate times.
Wishes can come true.