It appears the most popular RKive.IT units are the 500GB and the 1TB ones as most customers are using these not for a full server backup, but for essential data for long term data archiving.
NAS device availability
We have had a little rush recently on these units, and will build some more. To check on availability, please see our new availability webpage. We will always take an order and build you a RKive machine, although there may be a little delay whilst we source new 500GB or 1TB drive parts.