We have a Realpresence 310 that we use to connect to offices from 08:00 to 18:00, 5 days a week.
I have been asked if the sessions can be recorded as trading information is being discussed.
After a quick look around I see the monitor output on the 700 can be used direct to a DVR, but this is not available on the 310, also I would be concerned about the files sizes as we are talking about 50hr a week of recording time. and as yet I have not been told what retention period is required.
You are correct, the GS 700 has a specific output for recording, which includes the video and both way audio. There are ways to use any endpoint product and do recording of the calls.
The question about storage would be up to the device you would use for the storage. Polycom has an on-line recording device, the RealPresence Media Suite, see <here> for more details about the product. Contact your Polycom reseller for more details and a demostration of the product.