There are a few solutions to power these servos with older type ones. One is for the mfg's to upgrade some of their power boxes to have HV going to the main channels while lower voltage going to other servo channels. Or using seperate regulators to regulate the power going to the older servos and leave raw voltage going to the HV servos.

I think that these HV servos are a great idea and they do have a market out there. I also think that the radio companies have missed a great oppertunity to change the sevo plugs to a higher current carrying ones (to achieve the most/best efficient use of the power available)[>:]