Errrrrr, that's not how networks work. You can't push from one end, pull from the other, and expect it to be any faster. There is a maximum amount of bandwidth in each direction, and you can't "contribute" upstream bandwidth to give more downstream!

Splitting it over ethernet/usb would be a nightmare, and wouldn't result in 2x performance - USB heavily loads the empeg with interrupts and would slow down ethernet transfers.

It's 10Mbit as 100 is really not necessary; the empeg is not a fileserver. Also, 100mbit chips are much more expensive (we're talking about ones that will interface to an ISA-style bus, ie they have at least 64k of packet buffer, etc - PCI ones are cheap, but there's no PCI in the empeg. For ISA-style ones there are only a couple to choose from), physically larger (no integrated PHY, etc), and cause lots of EMC headaches.

Hugo