Getting a "portable" /19 or /20

Ignoring the (incorrect) Juniper references for now because they are
trying to do bigger and better things (if you want to fill a box with
OC192 or 10GigE this is not an option), the only flatout "limitation"
really is bus speed.

There is no reason you can't do sufficient longest prefix match lookups to
route a gigabit, or process packets fast enough. Infact if you were really
serious, the Netgear GA620 card is really an Alteon Tigon 2 and the
firmware code is open source. There is absolutily no reason you can't do
packet processing on the card itself, and DMA the packet data directly to
another card. You could implement near linerate filtering, duplicate dCEF
on the card itself, and lots of other nifty tricks... None of these things
are technically or programably unfeasable.

Of course you would probably immediately take this little box which cost
you next to nothing to produce and sell it for the same obscene amounts
that most imbedded FreeBSD systems go for, to people who didn't understand
the technology.

Like I said, just because YOU don't know how to do it with the OS you've
always installed and a perl script does not mean it can't be done.