Thanks for the nice comments.
Currently, the smallest hardware option for mTrax would be a NetBook with XPSP3 or Win7, and preferably 2gb of Ram.
Many NetBooks are priced between $200 & $300, which make them attractive.
Other hardware options, such as the ones you mentioned, are being considered but there is unfortunately no scheduled release for the near future.
Making mTrax available to many platforms remains one of our main goals.