Hello,
have a look at the "Cisco 10000 Series Channelized OC-12-STM-4 Line Card" at
http://www.cisco.com/en/US/products/hw/routers/ps133/products_data_sheet09186a0080089038.html
or at the "Cisco 10000 Series Four-Port Channelized STM-1 OC-3 Line Card" at
http://www.cisco.com/en/US/products/hw/routers/ps133/products_data_sheet09186a0080089027.html
It will allow you to have up to 768 channels (like DS0, DS1, etc.) per card and up to 192 channels per port.
In cooperation with your SONET provider you could setup a couple of OC3 links instead of 800 physical E1 interfaces. Redundancy features like APS 1:1 are available as well.
Hope this helps! Please rate all posts.
Regards, Martin