I know some HDX900 and Varicam owners who are using the nanoFlash. A DIT told me yesterday that it was a bit buggy. It's a good way to extend the life of tape based cameras or improve the recording codec for an EX1 or EX3.
However, it's still 8-bit, and at the minimum bit rate needed for I-Frame, it is not more efficient than P2 cards in Native frame rates using AVC-Intra 100 at 1080/24PN, 10-bit, full sample 4:2:2--both are 40 minutes per card. nanoFlash is MPEG-2 based vs. AVC-Intra which is h.264/MPEG-4 based and I've read the latter is twice as efficient at the same bit rate, meaning less compression.
A 32Gb CF card costs about $200 vs. $600 for a 32Gb P2 E card. If shooting over 100Mbps with the nanoFlash, you have to use a special 16Gb card.
Panasonic P2 cameras can hold five cards, or 200 minutes of 1080/24p with 32Gb cards, 400 minutes with 64Gb cards. Having internal solid state recording is more convenient, very reliable and five 32Gb P2 E cards is about the same cost as the nanoFlash, assuming one owns a P2 camera already.