I love the Mu SL. Although I don't have a lot of experience with high end nonfolding bikes, the Mu SL is certainly the best bike I've ever taken for a test ride.
Still I think I'll have to pass on this opportunity to grind a few thousand dollars of Dura Ace components and custom Dahon ceramic bearings to bits. I'd easily pay $3,000 for a 16 pound folding commuter that rides like the Mu, but not a race bike that I can't actually ride without gradually running it into the ground.
I'd certainly go for a frameset if the magnesium alloy proved durable, but who knows how an unproven material on a limited edition bike is going to hold up. On the other hand it's hard to go wrong when it's backed by a lifetime warranty, especially when the frame is about a pound and a half lighter than its aluminum counterpart (or so I've seen it advertised...how heavy can the aluminum mu frame really be that the magnesium one is 600g lighter?).