Remote management cards with PoE

There is a a thing i´m not aware if this is available somewhere, but i see a gap at a certain point in building servers. It´s the way, remote management cards are powered. They get their electricity by the power supply of the computer. It would be more sensible to power them via Power-over-Ethernet, when available. By doing so, you would be able to completly disconnect the power supply on the primary side from the power grid.