Speedball pen. You can get various tips for them from very fine to the caligraphy style. Use paint instead of ink. Whatever paint you used on the plug, use in the pen. No compatability issues. Sign right on the painted plug, then clear the whole thing.
Thanks everyone for the input! I used an ultra fine Sharpie on my lure I just finished. The Devcon went right over it with no issues at all. I'm going to grab a caligraphy pen too and start messing around with that. I'll see if I can get some pictures posted.
The materials displayed on the Tackleunderground Web site, including without limitation all editorial materials, informational text, photographs, illustrations, artwork and other graphic materials, and names, logos, trademarks and service marks, are the property of Jerry Goodwin Inc. or its parent companies, subsidiaries, divisions, affiliates or licensors and are protected by copyright, trademark and other intellectual property laws. You agree not to reproduce, retransmit, distribute, disseminate, sell, publish, broadcast or circulate any such material to anyone without the express prior written consent of Jerry Goodwin Inc.