I managed to find a company in the Netherlands that appears to have a pack of 3 N810 styles pens. If you browse to http://www.telecomforever.nl/ and search for "n810", you'll find a bunch of N810 accessories, including the 3-pack stylus package.

Unfortunately they only sell to distributors. Swell. I just sent an email to them asking if they have any resellers within the US that I could purchase that from. Hopefully I'll get an answer from them. If I do, I'll post that information here for anyone else that's also looking for replacements.