Build 1631 is called beta 2. 
http://snapshot.opera.com/windows/o100s_1631m.exe
http://snapshot.opera.com/windows/o100s_1631.exe
It is not officially announced at the Desktop Team blog or elsewhere. That means it is one of the stepping stones towards beta 2.
I do like the darker colour. I think the new skin is moving towards an integrated entity. The panel now integrates seamless; I donāt see the skin when I am not focusing on it nor is there anything that distracts me; yet it is there with an appealing simplicity when I do focus on it.
On a side note. The status bar is a bit too slim right now. On my 1024*768 screem it could do with one or two extra pixels in height.
Like build 1535, which was the first beta, released one week before 1551, the official beta 1. 
it is by now.
Nice build again. If you happen to hate the error pages, too, look here.
opera:about says Opera 10.00 Beta 2, though.
The beta 2 addition was already discovered with previous snapshots. Unless it is announced as a beta it is still a snapshot leading up to what is going to be beta 2.
They have disabled Unite for this build. It is too unstable for an official beta build. I guess it will be back for testing in the first snapshot after beta 2.
New build after beta 2:
Hooray for the beta 2 plus Unite build for the hard core Opera fansā¦
1679:
JoWa or Opera? Iād say both. 
1691
Running OK. Fault with wrapping tabs has been fixed but the ā ā ā ā ā ā Menu button now wonāt go away!
Same here. I did manage to remove it in earlier snapshots, donāt remember how. Now it keeps coming back. 
Beta 3, Build 1699, is available from ftp://ftp.opera.com/pub/opera/win/1000b3/
Iāve just got the Classic En version. Itās not yet on Desktop Team.
1703:
Browsing with the Beta 3 + Unite (build 1703) right now.
I guess it is a good thing Unite kinda āstallsā Opera 10. It means that meanwhile lots of other bugs also get solved providing for a rock solid final release of Opera 10.
I think the menu button on the tab bar is extremely annoying. Just canāt get rid of it, which has been confirmed at the Opera forum as far as I can tellā¦ well, the workaround would be to hide the tab bar. Thatās out of the question though. I want the tabs. Or, I could enable the menu bar, but I donāt want that either.
:-TD
Yes, 1703 has Unite and I donāt want that, so I was happy to get 1699.
I hope that thereāll be a Classic version without Unite for the Final.