Well, Spriteman, the rule about waving the metaphorical todger (eg. PC capabilities on minor platforms) about is that it only impresses people if those people are actually looking. In other words, Acorn went to a lot of effort for little effect with their PC card add-ons, whereas they could have impressed more people if they'd kept things relatively simple and said, "Here's a Risc PC with two ARMs in it." They could have dropped the "open bus" complexity and concentrated on the SMP issues with two identical processors directly. I believe the A540 had two slots for processor modules, even, so it was a shame that Acorn got sidetracked.
Of course, people are going to say, "ARMs aren't good at SMP." But then I'd recommend such people to read that last paragraph again properly and also to consider the fact that ARMs and 486s probably aren't designed to share the same bus either.