The split turbine is actually very common in miniature turbines. The separate the compressor and turbine to make space for the combustor. And yes, I am talking about radial turbines.
Nothing new really.
Ok now...
Back onto the issue of Charging the ERS using the Toyota LMP1 solution.... It is very simple.
There are two options:
1) Front wheel KERS - the Majority of the braking energy comes from the front wheels. You will get more than twice the amount of energy recovery by applying KERS to the front wheels. As a result you will end up with four wheel drive cars however, if the regulations allow.
2)
You attach an MGU-H to the Naturally aspirated V8 engine with a bypass valve. Unlike a turbo-charger, it has no compressor, only a turbine. The turbine would be designed to be very small and restrictive. So you do not want to send 100% of the gasses through it. And due to it's parasitic nature, you only want to divert a small portion of exhaust to it when you are charging the batteries or sending power to the KERS or at low rpms. The branch of pipes going to the turbine would be only large enough for a portion of the gasses to go through so most the exghaust gas is bypassed keeping the NA sound.