The Limebook was a nice idea, but it had one major drawback:
the makers of it stopped making it.
That tends to be a pretty major flaw. 
The initial investment required to restart production would have been huge, and the resulting price point too high for its specs.
What is the LimePC Z9 listed on their website -is that similar to it? The site states it has a 800mhz PowerPC MIPS processor, which I find somewhat confusing.