If I am understanding correctly. Why don't you just X-ref all your individual drawings into a single drawing.  This way any changes made on the single drawings will be updated in the X-ref. Then you can set-up individual layouts on each drawing you have inserted. 

You want dwg with several model spaces?

Why not just paste all drawings in one dwg but in different locations in model space. After that you can edit all of them in this drawing, you can made different layout with viewport to any of drawing, and even you can edit any of them through corresponding layout (viewport), just like you do this in excell sheets?

If you want to compile sheets into 1 DWF file from various DWG files, use "Publish" command:

1. Type Publish at the command line or click on the Publish icon.
2. A dialog with all of the sheets in the current drawing will appear in the main window.
3. Re-order or delete any sheets listed for the specified DWG file.
4. Click the Add Sheets button from the right.
5. Navigate to the DWG files you want to publish from. Select each file.
6. All of the sheets in that file will now be added to the main window where you can mange them as one set.

Hope above will help.