Hi Dennis,
The Cisco 4948-10GE is shipping out with X2-10GB-LR which is 10 Km on SMF, the WS-X6704-10GE is shippped out with XenPAK 10 GE Module. You can establish the optical connectivity between the 10GE-X2 and the XenPAK Module.
You can also refer to the attached ZIP File that contains a PDF on Cisco Catalyst 4900 Series Switch.
Thanks and Regards
Sriharshaa Prabhakar
Technical Specialist - Networking & Security
Enterprise Services
Wipro Infotech
Mission Road
Bangalore
Email:-sriharshaa.prabhakar@wipro.com