Following from the recently leaked Desire HD system dump, the animated HTC Sense flip clock has already been ported - and confirmed to be working on the Droid Incredible.

The new clock features numbers that actually flip down as each minute and hour passes and XDA forum member thatdudebutch has posted a link in the forum to download the zip.

Note that you must be already running HTC Sense for this port to work.  Moreover, your cached prior HtcClockWidget.apk signature verification is required, so you must not wipe and should have the stock widget active on your homescreen before flashing the update.

For more information and the download link, take a look at the forum thread.