I don't think business has slowed due to the economy. It may be a small part of it, but I think business in this particular niche has slowed as a result of the Chinese-made pipes. Even some of the well-known and respected vendors have turned to selling them. In the face of that competition nobody can afford to profitably market their own U.S.-made product built with quality materials (polishing a piece of metal does not improve its quality) and with quality labor (i.e., people who can weld correctly and do it consistently). But I digress.....
If you really need to have a cat on a car, get a downpipe from just about anyone (Chinese-made or otherwise) and hack 3" off of it. Then a standard-length cat will fit. I had 3" Random Technologies cat and a shortened THDP for years. The only problem is when you move to a dump/test pipe. You'll need to have one custom made to accomodate the extra length.
Jim