Becoming a "billion dollar company" isn't much of a stretch, IMO. The solar glass market won't be homeowners "going solar" but big buildings with big budgets.
On the other hand, I have a tough time thinking of any pink sheet company, particularly one that's in debt to Cornell Capital Partners, as a "good investment".
I've successfully traded XSNX and currently hold shares (average pps - .29). In my opinion XSNX is attractively priced at this time.