I wrote an article for Snowshoemag on geocaching: http://snowshoemagazine.com/view_content.cfm?content_id=43. I do think it would be a fun event for families. I wish I had the time to organize one in Colorado.

I set up a snowshoe-able cache in one of our county parks right before Christmas. So far it has been found by skiers, hikers and snowshoers!

Great to hear there are others out there! It really makes the hunt even more fun. In fact here is a pic from a first to find I had earlier today! Enjoy
http://img.geocaching.com/cache/log/8e95b9fc-9bd6-4d57-bcb7-a850e10e4439.jpg