I did. Also currently there is no “minimal SBT” standard. Pretty much all of them inherit basic ERC-721 token which has a lot of redundant functions for an SBT. Like why do you need approve and transfer methods when the token is ideologically non-transferable?
We actually took a one step further and implemented this minimal SBT contract here.
However, this does not provide the “automatic expiry” use case which I think has a lot of potential.