adrianl: I agree, despite the many technical challenges to it. An open source RISC OS would at least give that option with a couple of committed OS experts working on it.
jess: with the core OS running natively on a multi-GHz dual-core chip (a la the recent Apple line), I don't see any reason why applications couldn't run faster than native on some nebulous RISC OS/x86, using Rosetta-like emulation.
It's hard to believe exactly *how* much faster other chips are than current RISC OS hardware (even this 1.42GHz G4 in a 2 year old Mac mini), and what that gives in terms of capabilities of software. No, it's not needed for emails, but Java and Flash both enhance the web experience and faster's always better there. Ripping DVDs, whilst playing back smooth high resolution DivXs becomes possible, editing video on consumer hardware etc. etc. Desktop RISC OS on ARM has no future apart from absolutely tiny niches at best. Personally I don't care what software my STB runs, as long as it does the job.
The other *big* advantage to an x86 port of RISC OS would be the binary-only software which theoretically could be run in an appropriate container. This is done by mplayer on Linux (for example) to get full codec support by dropping the Windows DLLs in an appropriate folder.