No, not for a 3G adapter, but for one that goes from USB to Ethernet cable.
jcsullins compiled it for me, by the way, so I no longer need the driver (many thanks to him).
However, I can confirm that ICS on CM9 recognized it without problems as eth0 and once I ran dhcpd and assigned a DNS server, I had no problems connecting to the internet. So feel free to add a driver for your own adapter if you have one.
So to review:
-copy driver (to /system/lib/modules)
-insert module ("insmod /system/lib/modules/*yourdriver*.ko")
-get an IP address (manually, or "/system/bin/dhcpd eth0")
-add DNS (setprop net.dns1 *yourDNSserver*)
A couple caveats, I've noticed.
1) It doesn't play nice with wifi. I sort of expected this, but bringing up wlan0 and eth0 at the same time crashes the tablet.
2) Not all apps recognize the internet connection. This is a bit frustrating since most do (including the Browser), but not all.