In some email I received from Greg A. Woods, sie wrote:
[...]
> As always though there's the (perhaps minor) need to consider what the
> other *BSDs are doing and planning to do, at least to the extent that
> binary compatability is necessary or desired.
[...]

In FreeBSD they use the symbol table as a means for registering sysctl's.

Let me know if you want a brown paper bag.

Darren