There is a much cheaper and effective way to support multiple IP addresses
per interface: number and bit mask, e.g.

        ifconfig le0 ipaddr 192.1.1.16 hostmask 0.0.0.15

for this example, the host would accept 192.1.1.16 through 192.1.1.31, and
it would only cost you a mask & compare to implement. Granted, this only
works for ranges of addresses, but given how cheap this can be, and that
you can easily assign ranges of addresses on a single network...

        just a thought,

        Erik