Coralife digital works well for me, but not suitable for this application.
Assuming that a SCWD won't do it for you, what about this?
http://www.jlaquatics.com/phpstore/s...duct_ID=wm-nwt
By the way, I assume you've solved this problem, but I notice they're selling egg tumblers at canadianaquatics.com.
Regards,
Nevin