Would be REALLY nice.  OpenBSD bumped up a while ago (2 years?).
It took some work to catch things that hardcoded 8 char arrays
for user rather than using the right #define, but worth it.

No reason I see for not going large - like 128 bytes (long double
byte names may be desirable).

Is it (`grep LOGIN /usr/include/*.h`):
/usr/include/limits.h:#define   _POSIX_LOGIN_NAME_MAX   9

that guides it?

Quoting Perry E. Metzger (perry@piermont.com):
> 
> "webmaster@datazap.net" <webmaster@datazap.net> writes:
> > I set up a machine running NetBSD 1.6 on a Sparc station 20. I then
> > migrated all the users from a mandrake linux system to it. The problem I
> > am having is there are a large number of users that have user names of 17
> > characters or more. In NetBSD I am only able to get people with user names
> > of 16 characters or less to work.
> 
> That is correct. We only support 16 characters or less as shipped. You
> could tweak a few things and recompile your whole system, at the cost
> of being somewhat ABI incompatible with other people's machines.