byoweb,
At this point we are focusing on invoicing as the core component of the product. If you have a .NET based ticketing system that you'd like us to look into integrating, we could do that. That is much more feasible for us than to build an entire ticketing system.
Check out SmarterTicket from http://www.smartertools.com.
TJ Havens
TJ and byoweb,
We've added a ticket tracking integration into our feature request system.
What integration points would you be looking for between this type of system and DotNetInvoice?