hi bruce,
i am assuming you are talking about analog modems. you can buy hawking technologies's
dual analog router it requires this product about $149 and two 56k external modems.
or you can get a 3com product which has dual built in 56 analog modems it is about $350- $400.
it is not cheap but if you have a lan with a e-smith on it then all you need to do is setup say the 3com make that your gateway machine and let e-smith act as a standalone server.
i am not that sure if e-smith can do "channel bonding" i know under win2k and nt4 you can do it. where the
ppp dials out both modems simultaneously and grabs one ip address.
hope this helps some what.
raj