In terms of range, the date can fall anywhere beween the present date (ie. 20030930, or is that 030930....see the difficulty?), and the most earliest date accepted, which is Jan 1st, 1900, so 19000101. Since a numberic cannot start with 0, this date cannot be represented by droping the century indicator (ie 19xx), so 000101 is not accepted.
This is a bit difficult to implement as a numberic. Let me know if you have any ideas. Thanks for your feedback.