There is no official cheat for it, and there may be a reason for that. As far as I am aware there is only one program currently that removes that limit, the effects of which can be seen here (reposting links from another thread):
LinkLinkAs you can see it really messes up the creature. I actually found the program and tried it, and found you can get two or three extra parts on there before it happens. It
may have something to do with the game knowing you've broken the limit. (When that particular program is used you can add all you want, but the meter still increases and if you go to save with extra parts it won't let you, stating there are too many.) So it's possible, I suppose, if you actually had one that instead told the meter it was not filling rather than to disregard the limit that could help, but I somehow doubt it would be that easy.
EDIT: For the fun of it I fired it up again. Playing around it seems more complex parts (i.e. a whole arm) do warrant a faster descent into madness, lol. On the other hand I could put on quite a few more smaller parts (weapons, details, etc.) before the same thing happened. It may simply be how much has to be rendered on one versus the other and probably is, but maybe it does mean a tie between the meter recognizing a creature surpassing its limits and how quickly and how much said creature gets broken.
[Edited by RobSmith176, 6/20/2008 9:03:35 PM]