Just went through the same thing. I eventually found a cheap pair of 175mm XT cranks to steal the 5 arm 94mm BCD spider from. I have also seen the integrated chainrings for a reasonable price, some listed on ebay US recently for $35 shipped.
I have a decent condition large spider/ring that came off my 170mm cranks, although it might be an LX. Was thinking about doing horrible things to it with a saw and grinder to use as a single speed spider. If someone needs it just shoot me a PM.