They aren't releasing specifics regarding how many more machines will be added or what types they will be, but anything above their existing 5 units should be embraced:
"What's been announced to date is not the full extent of what we will see over the next couple of weeks and months," Shuttleworth said during an interview. "There are additional offerings in the pipeline," he added.
These are good signs. The largest Dell's choice for preloaded Ubuntu systems, the better someone looking for one will feel. And, the more Dell has to offer, the more their competitors will want to offer something that matches it.