One of the concepts a related project explored was using live / persistent USB disks to preserve student ownership and facilitate unscheduled explorations.
Multiplexes hardware across students at different times, facilitating students using a consistent environment at home on old P4 desktops and at school on whatever's available.
Even large (32+GB) portable storage devices are available under $50.
Check out "sugar on a stick" and "open1to1" for related trains of thought.