There’s a better way to do it than @illdred posted. It can be found easily here;
As @coasterspaul stated, this isn’t supported, but at the same time isn’t causing problems either, as I’ve had infinite inventory on for a while with no problems.
The cap was implemented back before we had a lot of storage items. That being said, it’s original idea was for stockpiles, and thus to limit the number of items needed to be rendered, thus lessening the CPU load. A lot of optimization and storage options have happened since then, so may this will be an item that will be retouched with everything else.
If you do a search, there are MANY MANY MANY other posts about all this.