Site-specific browsers should simplify testing of some types of web applications, e.g. those which support multiple registered users. On platforms such as Mac OS X, which typically run only one instance of each application, SSBs should allow you to launch multiple, distinct applications which point to the same website.
Is anyone doing this? Is it better (and does it always suffice) to simply run multiple copies of a twill script, and to dispense with browser-based tests?
I haven't tried Fluid yet, since my main work machine is still running Tiger.
Alas, I guess basic Prism apps won't do the job: