Not to be a naysayer (because I don't know the hardware specs and it may in fact be possible), but my understanding is that the 6-frame limitation is related to the amount of memory available to the camera. The DCS-942L, which has a microSD card for recording, allows for video clips to be e-mailed on motion detection, including up to 5 seconds prior to the event.
I'm not 100% sure what you're implying, but SD card reader does not factor into the ability of the DCS-942L to email video clips, as no SD card is required to use that functionality. The DCS-933L, the successor to the DCS-932L, has no SD card reader and can email video clips. I presume that email/FTP of video feeds is a memory constraint, but since I cannot validate that hardware limitations are preventing video feeds, I added the line item to the firmware wishlist.
Memory:
DCS-932L: SDRAM = 32 MB; Flash Memory = 4 MB
DCS-933L: SDRAM = 64 MB; Flash Memory = 8 MB
DCS-942L: SDRAM = 128 MB; Flash Memory = 16 MB