Which SDXC card is required for the BMPCC ? 30 45 or higher MB/S ?

No one really knows. John Brawley says Sandisk Extreme Pro, but the website says Sandisk Extreme. it will probably depend on final testing after the DNG RAW is fully implemented.

Thanks. I was thinking for the Pro Res rather than for the Raw.

It's not officially known yet, but these are (well educated) best guesstimates:

ProRes (220Mbps HQ): at least 35 MB/sec write speed
Compressed RAW DNG (1.2:1 compression): at least 70MB/sec write speed, faster is recommended.

As with everything at this point: best guesstimates. No guarantees. No promises.

Are there even 70+mbps SDXC cards yet? I am not sure what speed the Lexar 600x is, but that seems to be the fastest one I can find.. at like $100+ for a 64GB it's not cheap. I'd want at least 2 256GB cards to be able to record for some time.

Other thing is, how fast will these transfer to the computer? I have a USB 3 SDXC doc, but it's not fast by any means.

I've ordered a couple of these.

SanDisk 64GB SDXC Memory Card Extreme Pro Class SDSDXPA-064G-A75

The SanDisk 64GB SDXC Memory Card Extreme Pro Class 10 UHS-I provides photographers and videographers with a high-speed SDXC memory card rated up to UHS Class 1, offering up to 95MB/s read and 90MB/s write speeds. This high-capacity card is specifically engineered for sustained burst shooting modes and HD video recording.