Well, yeah...they can, unfortunately. For example, Rocky Mountain Bicycles offer a Sherpa in several flavors (
http://www.bikes.com/main+en+01_102+SHERPA_30.html?BIKE=852&CATID=2&SCATID=26 )
It happens all the time amongst bicycle manufacturers, not just with model names but entire brand names.
Before being absorbed by Western States' Diamondback division, my Centurions bore the same name as a number of later imitators. The current producer of bicycles under the Centurion name is a German firm (
http://www.centurion.de/en_int/cms/168/about_centurion_history# ) whose history would seem to actually predate the more widely known and marketed American brand.
I often see this on America's West Coast, as various Chinese mass-market imports bear names very akin or identical to historic labels. The Schwinn brand name has changed hands so many times, it is hard to even keep track of the current trademark owner.
Best,
Dan.
