I don't think I've ever had more than 200 layers, so i can't say I've ever needed or run across that command before. Nothing in my Help File or System Variable editor seems to come up with anything. However its possible that the problem no longer exists in the later releases, so the variable was then removed.

If you have Express tools installed you can take a look at all the variables yourself. From the Express Pulldown, select Tools, then System Variable Editor.

Nested layers? nope. I'm not sure what you would use them for, unless you need the ability to manipulate multiple layers at once by manipulating the parent layer. You can do something like that inside of Layer manager in 2004 and above by setting up layer filters. You create the filters yourself based on whatever criteria you decide such as color, xref, wildcards, etc. They are pretty handy. The only problem is the number of layer filters can get way out of hand when importing from other people's drawings and it slows layer manager way down. I wrote a few lines of code into my lisp routine which deletes all layer filters when a drawing is opened. its not a great solution since it makes the filters temporary in our office, but it beat the alternative. However the filters may be just what you need if you are dealing with 200+ layers. I'm not sure if 2006 or 2007 has dealt with the slowdown problem yet, that's something I'll have to check in to.

Datamine looks pretty powerful. I've always considered Autocad the Swiss army knife of cad. Specialized programs may be much better for specific tasks and if that is the only task it may be better to go that route. I have never used AutoDesk Land Desktop, so I really couldn't make a good comparison though. Let me know what you decide.

Steve G.