Hi Ed,
I can highly recommend La Classique which is in Montreal, Canada as a good comp for champ level seniors (not too sure about syllabus and pre-champ events as I didn't see them). It takes place in mid-February. My partner and I competed there this year and were very pleased with the size of the field (there was a quarter final which apart from the US nationals is just about as large an event as we come across). There was a very good couple from Germany among the competitors and of course a number of competitors from the USA so foreign entries do not seem to be a problem. Montreal is a wonderful city to visit with a charming historical area and many cultural attractions - though it can be terribly cold in February.
The Manhattan Amateur Classic which will take place in January 2003 is also another excellent comp for seniors. As long as you are a member of your country's amateur dancesport body then foreign entries are not a problem. This past year there was a quarter final at that comp as well. And of course New York is an amazing city!
Best of luck with your plans. I hope to see you on the floor!