More than two Ethernet interfaces on a 28xx router?

Hi,

I am currently using a 2611 where one FE is connected to my local LAN and the other is configured as dot1q trunk with approx 15 subinterfaces. This works like a charm, the traffic towards each remote site is mostly M&C, i.e. not bandwidth intensive. No routing between remote networks, the only traffic is between my local LAN and the respective remote networks.

Now I need to perform the same trick towards another set of remote networks. I need another ethernet interface on my router, running dot1q and with somewhere between 15 and 30 subinterfaces. I'd like to purchase a new Cisco router for this task, but I don't know how far up the ladder I need to climb to get a router with more than two Ethernet interfaces. From this page

doesn't look like the 28xx series support LAN network modules at all, as opposed to the 38xx series Unfortunately, I don't have an NM-1/2FE available for testing in my 2611. I know from earlier that it didn't recognize an older Ethernet WIC that I installed into one of the WIC slots.

Related to this: Is it possible to use a 3550 like this (router-on-a-stick)? On my 2611, I create as many sub-interfaces as I have VLANs to route, and on each subinterface I configure the following:

int fa0/1.501 encap dot1q 501 ip address