If there is one to be found Luke can find it.
PM him directly at Lindsay Cadillac Parts.
I think the primary difference between Seville and Eldo would be the length of the body.
The two-door should have a shorter wheel base, if it is a complete exhaust you'd certainly have an issue. If it is a service cat then it shouldn't matter.
I know in the US EPA says it has to be designed to work on the car it is to be installed on, again not sure on Canada law.
Putting two cats in is the most retarded thing I have heard today.. but it is early.
I know what you mean though, I would do the same thing.