It would be a huge step forward for your your component to add a VAT feature with a freely configurable VAT/tax percentage in the backend. This way your component would become usable for more professional shops.
I´m selling digital goods/downloads only but may be someone would like to use it for selling non virtual goods too and in that case adding a shipping fee would be cool too. Some small features and easy to implement but for sure it would increase drastically the amount of your potential customers.
Can´t believe that I´m really the first to suggest that!
PS: I would be highly interested in an affiliate sub-system for DMS!!!!