You are right - adding/modifying files in an MOSS farm manually means that you need to modify each server in the farm individually.
You can either use batch deployment or you can create a new editor solution package and include all the additional resources by default.
The batch deployment option is easier to implement - simply create a new batch script and use xcopy to add the new files to all front end web servers.
The new solution package is a bit harder to implement but is easier to deploy afterwards. Here is what you need to do:
1) rename the .wsp solution file to .cab
2) open the file with any archiving software (e.g. WinRAR) and extract its contents to a convenient location
3) customize the files for the solution (add languages, change config files, etc.)
4) To build the wsp file again, you need to run the makecab utility from Microsoft. Here is the full command line:
C:\windows\system32\makecab.exe /F RadEditorMOSS.ddf
The RadEditorMOSS.ddf file (Diamond Definition File) is also automatically generated by our build scripts. It is used by the makecab utility to select the files, which will be included in the solution. The ddf file is automatically generated on each RadEditor for MOSS build. If you open a formal support ticket, we can send you a copy of the ddf file for the latest build. Note that if you add new files to the solution package, you will also need to add them in the ddf file.
the Telerik team