Well I called Magura and they confirmed that there are no more RT8 or RT6 brakes in stock and that the brake levers are indeed unserviceable. The guy I spoke with was helpful and sounded a bit frustrated that Cervelo, in their wisdom, decided to scuttle a product that took a lot of time to design and manufacture. I think it's crap that and expensive, high performance bike like the P5 would have this problem with no apparent ez fix.
The rep suggested to me that others have tried, with success, to swap out the levers for the Shimano DI2 hydraulic lever/shifters. I've asked my LBS to order a set and give it a go. I'm a bit concerned as I've heard that it can be tricky...that there's no pad wear adjustment on the Shimanos like there was on the Magura.
Hopefully will find out whether this works this week.