Well, that didn't last long. The UK's short-lived alliance with Hungary is over after the latter's government indicated its willingness to take part in the proposed treaty change, subject to a parliamentary vote. Sweden and the Czech Republic (the only other two countries not to sign up to the process) had already done so.
Here's the key paragraph from the revised statement issued by European heads of state:
The Heads of State or Government of Bulgaria, Czech Republic, Denmark, Hungary, Latvia, Lithuania, Poland, Romania and Sweden indicated the possibility to take part in this process after consulting their Parliaments where appropriate.
In other words, the UK really is in splendid isolation. As Rafael wrote earlier, Cameron's non-deal has led us to the outermost margin of the EU and ever closer to the exit. Indeed, the more excitable europhiles are suggesting that's exactly where we're heading. Former Europe minister Denis MacShane has declared that there is now "little point in Britain staying in the EU. Bill Cash has won and I congratulate him and other Eurosceptics on their victory." If such talk grows, the pressure for an in/out referendum (as advocated by the Lib Dems at the last election) will increase.