You'd probably have to write your own javascript validator.
This is all CFINPUT really does anyway... so, if you don't know a lot about javascript, one method would certainly be to build the page with the CFINPUT validating to MM-DD-YYYY, open it in your browser and view source, copy the javascript and the now *INPUT* tag, paste the javascript back into your code then adjust it to validate the format you want (should be fairly easy).
Then replace the CFINPUT in your code with the INPUT you copied from the view source. It should have the newly revised function already called from a onX event.
Reload the page in your browser, and you should be in business.