It seems one of the reasons that it may have been pulled is because it can only currently communicate with other beta clients (i'm not sure which threads). Communication with the mainstream client appears broken, and LL is waiting until the hooks are compiled into the mainstream update before officially releasing it into the wild.

In it's current form it seems it can't communicate with most of the people in SL due to the extra hooks needed not being merged into mainstream sl. Considering how few folk are using the absolute bleeding edge clients on the main grid, it makes sense for them to keep it off the and avoid confusion.

So it seems to be... SLim works in the laboratory, and under laboritory conditions on the main grid, but not under everyday conditions yet.