It seems that almost as soon as registration for pre-ordering the Spark was announced, the initial production capacity was reached and registration was closed. The Spark sure is a hot tablet (if you'll excuse the pun)!
Aaron Seigo, a lead developer of the KDE project and the leader of the Spark project, announced registration for pre-orders on his blog on Thursday 16 February, and had to announce that the initial production capacity had been reached and that registration was closed only a few days later, on Monday the 20th.
Initially, Seigo and his company, MakePlayLive, had planned to service their American orders from Europe where they are based, but due to the phenomenal demand from the Americas they are working on setting up logistics in the US. As for the rest of the world, once Europe and the Americas have been serviced, the rest of us will be dealt with.
If, like me, you were unable to catch the pre-order registration, do not worry. You can still register on the MakePlayLive site, and you will be notified when the next batch of Sparks is being produced.