Turning an Ethernet into a WAN

[bill@ATHENA.PANGARO.dialnet.symbolics.com (Bill Wilkinson)]

I am looking for hardware and/or service recommendations in connecting
Lispms and/or other machines on different Ethernets via telephone and/or
other service. I want low cost point-to-point service, across town or
maybe between different cities. I want the connection at the Ethernet
level so I can route Chaos packets, IP packets, etc. Between Lispms, I
want mail service and file service and a single namespace for both
Ethernets.

Given than I don't want to pay for a T1 or chunck thereof, or wait for
ISDN to show up at my door, I figure that a 9600 bps (V.32) modem and
the public telephone network are acceptable.

I've looked at a few routing Ethernet bridges in the $2000 and up range.
These are high performance devices that are made for higher speed comm
media.  Thus the total hardware cost for bridges and modems for 2 sites
is in the $6000 range. Are there any cheaper boxes out there that I
should know about?

Has anyone out there successfully connected multiple Lispms on separate
Ethernets via routing bridges (locally or remotely)? 

Can Genera software deal with slow data rates gracefully or am I going
to find myself timing out at inconvenient times? What else do I need to
know or what questions should I be asking?

Has anyone implemented SLIP (serial line IP) for Lispms? I understand
that there are commercial services out there providing IP data services
at costs competitive with leased telephone lines.

Thank you very much.