I did manage to find out some bits and pieces about the clockport - it is an 8 bit interface, I believe it can cope with perhaps 2MB/s (which would figure given the Subway USB), also the Hypercoms could do 450kilobits/sec too.
my line of thought was putting a 10/100base-2 on there direct, or USB and a USB-Ethernet adaptor on me 1200.