Any idea to do the suggestion you give?
"Another method is to request a mining pool to mine it for you if the first 2 doesn't work out."
So you mean the transaction will be keep on network and will not rejected?
I suppose what ranochingo is saying is: you could contact a couple big mining pool operators, and offer them a bounty to include your transaction in the next block they mine.
I've seen this proposition many times before, but i cannot remember if somebody suggested which pool operator was open to such offers.
A miner can chose which transaction he'll include in the block he's mining, so this tip does makes sense if you find a big pool operator willing to help you out.