re: product to sell - may I humbly suggest something that has a subscription model. I've had plenty of chance to see "per seat" sales amount to little unless you have something truly unique and justifiably expensive per seat. A place I have done business with makes the majority of their income on subscription and or customer direct fulfillment (dev work on demand) and turns less that 10% on their seat based product sales, though they do ask maintenance once a year at the customer's option. The nutty success of Zynga on facebook with all those games is a great testament to microeconomic small fee subscribers. They're worth more than EA doing that silly stuff!
I forgot - happy birthday to your dad. Here's to at least as many ahead as behind on both his and Rockall's count.