I doubt that the 1000mbps will do any more than improve your image transfer rate from the card to your PC or storage device. I had a situation with my D700 where I needed to capture a large sequence in continious high speed (CH). The only way I found to do it was to use JPEG with all the processing turned off. The buffer fills up very fast with RAW, JPEG with some processing is slighty better and is best with JPEG and no processing. I was using a Lexar Professional 16GB 600x Compact Flash. It simply boils down to the transfer rate that the D700 is internally capable of.
There is no CF card that moves 1000mb/second that I know of. I think the fastest, the 1000x cards are rated for 150-160 MB/s.
The 1000x designation is based on the CD-Rom standard in which the performance of CD-ROM drives are measured in 'x' increments. 1x refers to the sustained write speed capability of 150 kilobytes per second. 150 kb/s x 1000 = 150 mb/s. although I have heard that some of these cards, like the Lexar's have hit 160 mb/s in some devices.
This is not the case in the d700. Here is Rob Galbraith's database measuring CF card write speeds in the d700. The Lexar 1000x cards top the list at about 42 mb/s. Good old and frequently on sale Sandisk Extreme's are a very competitive 38 mb/s at a much better price.