Lubuntu 12.04 isn't LTS release, but uses the very same components and repositories as all the LTS releases do, so you will get basically the same support as the LTS. Plus, the LTS does not seem to cover the 'universe' and 'multiverse' repositories anyway (as these are community based).
If you consider MATE desktop, you could have a look at
Point Linux which is basically Debian Stable with MATE and some Ubuntu/Mint-isms (sudo login, flash out of the box). I have good experience with it.
