Just looks like MS is fixing the market
The extra space on the SSD for the Linux model, accounts more for the price difference, and that extra space is kinda useful.
But, not offering Linux on the smaller SSD or MS on the larger does not allow the comparison to be between Operating Systems, which of course MS is pretty scared to do,
With the way Linux is actually installed and operates on the EEE, it may actually make sense to have a larger drive, Linux updates far more often and far more rigorously than MS based products. There is also a far larger collection to choose from so drive space is a bit of a premium. With that said I am sure there is something else behind this discrepancy of availability.
Personally I would prefer computer manufacturers to offer no OS on the system, and instead ensure that all the hardware specs are open, and write drivers for most of the major kernels. This should be a standard option on all systems, not something that is pretty much unheard of in the laptop and pre-assembled market. I am quite tired of having to format the existing OS which is an extra step in the process of getting a machine to work.