I tested what I suggested above and it works.
This is for the 4 CD version, eventually converted to DVD and using the Money fixed executable called No-DVD/fixed exe
To update your sims backupcopy succesfully to 1.1 do the following:
(note: after this you'll need a new fixed 1.1 executable that isnt out yet, but the purpose of this is to make your backup ready for a later update.
-Download the "thesims2_update_cd.exe" (only the cd version will work, even though you converted your 4CD's to a DVD installation so dont try the dvd version update.
link:
http://thesims2.ea.com/update/
-Create an image of the original Sims2 disc4 (labeled Sims2_4) using Alcohol 120% and select the Safedisc2/3 profile in Alc. 120%
-Mount the image in Daemon Tools 3.47 (press ctrl and shift on your keyboard to prevent the sims2 from starting up if you have installed it)
-Also copy back the original Sims2 executable from the original Sims2_1 CD to your installed program files folder or the update installation will halt on a error.
So overwrite the Money fixed exe again with original.
That's it, the update is installing correctly so you only need an image of CD4 where the update asks for when you start it.
So on your backup copy place a folder with an image of CD4, a copy of the original Sims2.exe and Daemon Tools 3.47 to be able to update later. Only thing thats needed later is a new fixed 1.1 exe or ofcourse the mini-image of CD1.
Note: Im not sure yet if a stripped or mini image of CD4 will work as I dont know if the update installation just checks the CD4 or needs also files from it to copy over during updating. But an image of CD4 is only 550 MB and a backupcopy on DVD of all your 4 Sims2 CD's is about 2.70 GB so there is space enough left to put a full image on it in a update folder.
cheers, E.