Had a bit more of a play… I realized that I am only getting 160-200KB/s when routed through the zeroshell Eee PC, using sshfs. I tried looking at top and there is next to no CPU being used, and very little memory. dmesg gives a pretty much constant stream of that earlier message “asix_rx_fixup()” etc. This happens whether I use a USB200M or a D-Link DUB-E100.
Other than that, it’s working perfectly. URL filtering is great, no slowdown on dansguardian, it all “just works”. With a new kernel or maybe even kernel module this would be working phenomenally. And realistically, for just one subnet it works ok as is. The maximum speed I can download is 570KB/s, which is not the full bandwidth but better than 200KB/s.