yeah, not directly configurable without turning on advanced options.
i think this is what you are after:
[font="Courier New"]
--advanced options get enabled
sp_configure 'show advanced options', 1;
GO
RECONFIGURE
GO
--'user connections' 0=unlimited, change to an integer value if you wanted, say 800 maximum
sp_configure 'user connections', 0
GO
RECONFIGURE[/font]
Lowell