In the past 3 to 5 years, whenever we work with another company they have an excellent Project Management tool where we can manage our projects.  Almost always it is Basecamp.  I think you should offer this to your customers in order to get projects done quicker, with better quality and testing.  Over the years we've had many issues with work we've had done by Convio, and I believe a tool like Basecamp would go along way and improving things.