Where can I obtain the latest version of the Ubuntu Ambiance themes or Ubuntu themes in general?
Specifically I am looking for a download of the 10.10 Ambiance theme for my 09.10 install and I have had no luck finding it with Google.
Not sure what you Googled for but I found this. It's a PPA. It has a 9.10 branch to it and they have the themes backported within it.
The last two lines are there to remove the webupd8 PPA after installation. It has a lot more than just the themes in and it might therefore upgrade a lot more than you want it to the next time you run update manager.
But if you run the last two lines, it should remove it from your sources and just leave you with the new theme files installed.
Given you want more-recent versions, your best bet is probably cherry-picking the packages you want from packages.ubuntu.com.
Download them all to a new directory, open a terminal, cd into that new directory and run