I've been exploring various gits today looking for examples of a superblock being added to an existing PoW blockchain.

We are working on a year-long development project that will add a PoS layer to our PoW base. Part of this new design will be a one-time superblock created at block height 'X' with the payment to a multi-sig team funding address.

Do you know of any examples where this has been done? Any developers who could be recommended?