Woohoo! The Winter '15 release has brought some changes to Environment Hub that clarify this:
The Create Organization dialogue now has a Purpose field:
For Development purpose there is only one option:
- Partner Developer
For Test/Demo purpose:
- Partner Enterprise
- Partner Professional
- Partner Group
- Consulting
- Enterprise Edition
- Professional Edition
- Group Edition
For Trialforce purpose we have:
- Enterprise Edition
- Professional Edition
