Will the BeOS run on the "Merced" processor?

Without a shipping version of the processor, it's simply not possible to answer this question. Intel's advanced Merced chips are not in any shipping products, and are not even available to developers so far as we know.

And while we would obviously love to run on the fastest processors available, it would be foolish for us to commit to something like the Merced processor -- which is a new architecture, not just an evolution of the existing x86 architecture -- at this time.