Bell (407) and Eurocopter (350BA) managed to get limited approvals ( unlikely that they would be approved today ) . The cost of adding second Hydraulic and second power generation would make it a very expensive option probably brings cost close to that of a light twin. The EC130 does have dual hydraulics so maybe the second alternator would not be too expensive. I am sure if the market was there someone would certify it.
Supplemental Type Certificate
Supplemental Type Certificate
Supplemental Type Certificate
Supplemental Type Certificate