Strange - my IYONIX connects to a Windows 2000 system via LanMan with *no problems*; can't think XP is different on that account. I use StrongED ans LineEditor and quite often as TaskWindow too - works perfectly. But I do agree the IYONIX pc still has the odd issue to sort out.
As for MDs "developed their own RISC OS compatible chipset": Well they did develop some things along those lines whereas Castle opted for available chipsets. I do not think that this self-made chip set is by default superior to ones available on the market place which are refined all the time by teams of developers. And to take one example: the graphics being memory mapped in normal RAM (that is no dual ported video RAM as in a Risc PC) means that with increasing screen resolution/colour depth the bandwith remaing for the processor diminishes - benchmarks do prove that the odd operation is significantly faster in 800x600@256 opposed to 1600x1200@TrueColour.
And unless MD manages to get some 32 bit RISC OS up and running I don't see them using faster ARM processors (until now I didn't see ARMTwister running and I read the odd statement from knowledgable programmers that makes it hard to believe that it will work - but I'd be deligted if it does work out and I don't say it can't be done).