My half-nybble's worth on this topic:

Some way to do this is needed, and the implementation offered by Perry
works well enough.  Aesthetically, I think I would prefer an
enhancement to the syntax of /etc/hostname.X to allow this. Something
like this would be nice, with various lines being optional:

---
ether nn:nn:nn:nn:nn:nn
inet hostname 0xnetmask linkflags
inet hostname2 alias
(others for other address families in use?)
---

They could just be lines that get tacked onto the end of
"/sbin/ifconfig <if> " in a loop, in which case the syntax above
changes slightly. To me, this is simple, general, and flexible, and
there's no need for more fancy shell code to make it happen or allow
people to pass weird or new options. Possibly, and to avoid confusion
when changing file formats, such files might be named like
"/etc/ifconfig.le0".

Bringing in another thread, this could even allow the possibility of
something like this in /etc/hostname.xx0:

inet `/sbin/bootpc -print-for-ifconfig` up



Comments, anyone?
--
Dan.