ABBA is a well known four letter brand. You could tap into the fan base with A33A. C3PO is another famous example. C33O (note O not 0) taps into a worldline of

ABBA is a well known four letter brand. You could tap into the fan base with A33A. C3PO is another famous example. C33O (note O not 0) taps into a worldline of history. 63PO also. Be careful with patterns such as I95W - you may run into traffic problems. IANL (another four letter combo) but you may have problems copywriting a sequence of two letters and two digits. See Intel 486. So how about trying Wombat Yancowicz?