That's impressive even for save game bloat :) I don't think I could imagine trying to play even at 50 megs, the 20 when I noticed was already really bad. So, go through your saves and find the point where they start increasing rapidly. It's obviously easier if you've got a lot of saves like I did, but the pattern I saw was that it was fluctuating between 10 and 11 megs (going like 10.3, 10.4, 10.2, 104, 10.5, 10.3, and so on) and then went 10.5 -> 11 -> 11.5 etc. Obviously your exact numbers will be different but hopefully you'll see something like that. If not, you'll have to guess more. When you've found it, play a little while (couple hours) with all mods still disabled, save often, and make sure it stays pretty stable and hopefully even goes up and down a bit. Then start re-enabling mods maybe a few at a time.