Unfortunately, the fields that are synchronized between Microsoft Dynamics CRM appointments and Outlook appointments are hard-coded into the application and cannot be configured.
Page 12 of the Microsoft white paper confirms this bad news.
But if you really wanted to go for it, you could build a custom application/Outlook addin that enhanced the Outlook appointment form with data pulled from CRM. We used to take this kind of approach with CRM 3.0 to sync the Outlook contact's Company field with the CRM contact's Parent Customer field, but it was a headache to develop, rollout and support for such a small benefit.