Btw, currently I don't consider this dropping means there has to be
a bug. It could be otherwise - a feature... e.g. when a new kernel
can transmit faster (then dropping in some other, slower place can
happen).

um... where would it be dropping that we wouldn't have a bug? I mean
sure faster is great... but if it makes my network not work right...

I've added all (I think) information you've asked for to the bug
http://bugzilla.kernel.org/show_bug.cgi?id=13835 except for ethtool
and netstat on the router side. ethtool complains about not having
driver or capability (maybe because it's a 2.4 kernel?) and the
version of netstat doesn't support -s. I disabled everything that I
can think of that would send/receive packets before doing the test
client side, except dhcp/dns windows box's were probably sending some
broadcasts too. but the traffic should be pretty low. I did remember
to set the txqueuelen didn't seem to make a difference

only error in dmesg I see is

e1000e 0000:00:19.0: pci_enable_pcie_error_reporting failed 0xfffffffb

but it's in working versions too.
-- 
Caleb Cushing

http://xenoterracide.blogspot.com