Ethernet Switch on PCI Card?

Hi;

Can anyone point me to a source of Ethernet
switches that are on a PCI card? I’ve seen them
in the past, but after numerous google searches
on various combinations of PCI, Ethernet and
switch, I can’t find what I’m looking for. I
would also be interested in ethernet switches
that slide into an available 5 1/4″ drive bay
and draw power from a drive power cable from the
PC’s power supply. Anything that let’s me get
a small Ethernet switch inside a PC would be
fine.

Thanks in advance…

-Hugh