In this case, use "Per User/Per Device" licensing, not "Per Server" licensing. You'll need 50 Server 2003 CALs (plus maybe a few more for service accounts and such).
Then you need as many TS CALs as you have users or devices accessing the terminal server(s), independent of the number of terminal servers you're running. Note that TS CALs are NOT concurrent, so you don't license the maximum amount of parallel connections, but the number of users or computers accessing terminal services altogether.
No, you need Server 2003 CALs as well as TS CALs, but if you're not using Per Server licensing, it doesn't matter.
Then you need as many TS CALs as you have users or devices accessing the terminal server(s), independent of the number of terminal servers you're running. Note that TS CALs are NOT concurrent, so you don't license the maximum amount of parallel connections, but the number of users or computers accessing terminal services altogether.
No, you need Server 2003 CALs as well as TS CALs, but if you're not using Per Server licensing, it doesn't matter.
The Ultimate Guide to Windows 2003 Terminal Server Licensing
http://www.brianmadden.com/content/content.asp?ID=154