Did anyone come up with a solution?
I see that you've asked this to find more answers to your question here:
https://bitcointalk.org/index.php?topic=5526402.0Unfortunately, the only solution to this is the one written in the first page:
You need a solo miner or mining pool to include your transaction to their block without relaying/broadcasting it to other nodes.
The last reply in your thread is the same as that solution, it's just specific to Mara Pool.
Both require trust that the pool wont replace your transaction.