I do recall seeing visual metronomes but my searches come up blank, and I'm not sure that
they have MIDI inputs.
However, there are a couple of options that might
First of all you could look at a MIDI to Light controller like this.
I'm not sure if it will do exactly
what you want, but the manufacturers might well be able to help.
Next up would
be a budget DMX lighting controller like this one from Thomann.
This has MIDI interfacing as well as lighting control. Again,
it is not clear whether or not it can follow a MIDI clock, but Thomann should be able to
tell you more.
And my third suggestion would be to go for a DIY solution. This example
interesting and is designed to do exactly what you want. And I am certain you could
achieve something similar using an Arduino which might be easier for a beginner.
Hope that helps.
When the going gets weird, the Weird turn Pro.