And, no, I don't know if Windows 10 is "legally" available for testing anywhere other than the Insider Program, but it's my guess it's not.
http://answers.microsoft.com/en-us/i...4-45f4b7ed2fb9 should explain things a bit better:
Will I be able to upgrade from the Windows 10 Technical Preview to the final release?
There has been some debate regarding qualification for the final release of Windows 10.
Microsoft has noted the intention is to provide a direct upgrade path from the Preview to the final release. Of course, decisions can change. Recently, the company noted that you could upgrade non genuine licenses to Windows 10, but later it was found out, that license would be non genuine.
So, to be on the safe side, its best you ensure you have a valid genuine Windows 7 or Windows 8.1 license installed in order to qualify for the final release. Company officials have noted though if you join the Windows Insider Programand upgrade from Windows 7 or Windows 8/8.1 to Windows 10, you will qualify for the free upgrade to the final release.
When asked if there would be a cut off date for Insiders before Windows 10 reached RTM, Microsoft's Gabriel Aul stated that preview builds would continue being delivered up until the final release.
"We expect to keep flighting builds to Insiders all the way up to RTM. More details to come, but no cutoff planned."
Before Windows 8, Beta Testers who filed bugs and suggestions usually got a free copy of whatever we were testing, but not always. It varied. However, we were never told in advance that we would or would not get a copy of the product. I've received a number of "SWAG" items for innovative suggestions, very, very, very good bugs. Those who regularly filed bugs were rewarded for their dedication with "stuff".
Recently, I had a very bad problem and aired it in one of my Beta Groups. Some 75 to 100 posts later along with a very dedicated fellow Beta Tester, we finally reached a solution. I gave kudus and praise for the help and assistance I'd received from this person. Bottom line, my fellow tester was invited to a very elite Beta Group.
What I'm saying is that not all of us actually deserve special treatment for testing Windows 10. Others of us, in my opinion, should receive some special consideration for going beyond the norm. Thing is, I think the SWAG days are behind us.
BTW, I wouldn't class myself as deserving special consideration . . . I just like testing and so far haven't found anything earth shattering that someone hasn't found before me.