Unconfirmed/pending transaction in MultiBit no longer exists, but my coin is still gone!
Use your backup to restore your wallet. Re-import your private keys and re-scan the block chain for your incoming transactions. If you can't find the outgoing transaction, then it was never sent and the coins are still in your private address.

If you have Multibit HD, then keep pressing 'receive' to generate a new address until it gets to the address that you received the coins on. Then it should show in your balance. I think you are using Multibit Classic though, so it only generated random addresses each time, and you would need your private keys for each address.