The only place I can recall seeing it in a restaurant was in Bloomsburg, PA.
I can't remember the name of the place and that was over 10 years ago. I
have seen them frozen at Costco though.
Haw.
I had a fantastic Beef Wellington in Chicago at The Bakery.
The downside is, it was in 1975. (On the up side, the spinach pie at the
Atheneum was terrific as well. In 1975.)
That's the last time I've seen a place offer it. A number of places offer a
"Portobello" Wellington (like, say, Carmelita and Cafe Flora), but it's odd
that nobody seems to want to do the beefy version.
-JAH