Alex,
Tightwad seems to be correct with 1998 as the last reference to the SwissBucks in the catalogs. Actually, the last pictures I can find of the knives are in the 1996 catalog. Pricing info was still available in 1997 & 1998 in the Suggested Retail Price List, but the knives themselves were not featured in the catalog those years.
In 1998 their were 15 models listed in the Price Guide - all with an indicator that it was a "discontinued item." If you're really interested, email me direct and I'll send you a complete list off the forum.
As a side note, something I find interesting - Wenger and Buck joined forces to produce the SwissBuck line (as Tightwad mentioned) - Wenger is the name behind the world famous Swiss Army Knife. In 1992 when the SwissBuck line was introduced (12 models at that time) you could also purchase any regular Swiss Army Knife from Buck as well. They were a distrubutor for Wenger. This was not the case, acording to what I can find in the catalogs, in 1993.