We will not be combining Data Bridge and Design Extender. We will eventually be offering 4 extensions and the Super Suite in our store.
The four extensions:
Data Bridge
Design Extender
eCart
Free Tools
We will likely stop selling the individual extensions over time. We'll work on creating tutorials and demonstrating the value that Data Bridge represents even for someone upgrading. I understand not wanting to take the plunge without seeing the new features, so we'll work on that and I believe you'll see it has more value than cost.