Look to Audi's Le Mans race cars for the diesel-electric hybrids.
I thought they were doing something with that. Supplementing turbo-diesel with electric power just opens up so many options.
The big issues with diesels are the lack of RPMs and the turbo-lag you're stuck with.
The influx of EFI tuning software has drastically changed the RPM issue (guys are seeing up 7k RPMs on the newer diesels...and that's on the big 6.6-6.7 liter v-8 and I-6 Duramax/Powerstroke/Cummins motors).
The only major issue left is the spool time issue with the massive boost numbers...seems like the immediately available electric power would be a perfect fix.
I realize that the P1 isn't diesel, but I'm still digging the electrical-power-for-performance-reasons concept.