Brian,
If you're not already aware of it, there's a weekly gathering at Ming's (near the corner of Montrose & Westhiemer) every Thursday. It has always had a strong Euro slant. I was a weekly fixture there for about 6 or 7 years. Haven't been in quite a while though - sort of took to riding alone. Anyway, might be worth asking around to see if there is still a strong Euro presence there.
This is another group that I'm more involved with.
http://autos.groups.yahoo.com/group/houstoneurorider/
Great bunch of guys.