It took 5 years to Cryptonote community to find the answer of the question raised in this original post.
But finally, the answer is here
"CUTCOIN".
The CUTCOIN is the first Cryptonote based project which as successfully implemented pure Proof-Of-Stake consensus.
In the Cutcoin consensus Wallet balances, transaction amount, sender, and receiver are private by default. Its innovative Proof of Stake consensus is the first to keep the total amount of coins even in staking wallets completely concealed. There is no minimum amount for staking, any amount above 0 CUT can be staked. The project has its own Staking pool which pays out every day.
The team behind the project has not stopped there, CUT COIN has successfully implemented privacy tokens on the Cutcoin network. This makes Cutcoin the first project on which has Privacy token functionality. The tokens deployed on the Cutcoin chain inherit all privacy properties as CUT COIN, MOnero, or any other cryptonote project, including RingCT.
Read project whitepaper for all technical details about POS and Token development.
Official website:
https://cutcoin.org/White Paper:
https://static.cutcoin.org/cutcoin-whitepaper-v1.0.pdfToken white paper:
https://static.cutcoin.org/cnt1-whitepaper-v1.0.pdf