Just a thought:

Ideally a miner is lurking here with a decent hashpower (lets say minimum finding a block every day) and is willing to facilitate this transaction. Feel free to define your terms and how to hand over the transaction safely.

I am sure there are ways for the miner here to prove his authenticity of hashpower control (e.g. by including a community defined text in one of the coinbase OP_RETURNs of one of his mined blocks and announcing it here before it happens).