here's another interesting section that may (contradiction is invited) address preorder.
§ 2-309. Absence of Specific Time Provisions; Notice of Termination.
(1) The time for shipment or delivery or any other action under a contract if not provided in this Article or agreed upon shall be a reasonable time.
(2) If the contract provides for successive performances but is indefinite in duration, it is valid for a reasonable time but unless otherwise agreed may be terminated at any time by either party.
(3) Termination of a contract by one party except on the happening of an agreed event requires that reasonable notification be received by the other party and an agreement dispensing with notification is invalid if its operation would be unconscionable. A term specifying standards for the nature and timing of notice is enforceable if the standards are not manifestly unreasonable.
I read this as, barring some huge unfair burden ("its operation would be unconscionable") or it occurring on some some agreed upon event (delivery of product, in the case of pre-order). With some kind of "resonable notification" (email or snail mail or forum post), unless other wise specified (SLA or delivery contract or Term/conditions) a seller could terminate the contract. One of the only ways, I think, that this could be argued against would be if the business unilaterally terminated all contracts of sale in an effort to utilize this as a "loop hole".
1) substitution of "a reasonable time" for lack of a specific delivery time
2) the contract does not provide for successive deliveries (like a subscription) so this does not apply, but it mainly says that a subscription contract can be canceled if it doesn't specify how many items or for how long the subscription is for.
3) just says you are in violation of the UCC if you decide to unilaterally terminate a contract and do not notify the other party. It does not absolve you of any responsibilities in the contract just because you notified the other party.
According to the UCC: failure to deliver means the seller must make restitution for the value of the contract, for the value of comparable goods, or arrange for comparable goods to be delivered if it chooses not to deliver the original goods in the sale contract.
BFL made the sale, the buyer paid in full, BFL did not deliver, the value of the goods rose, BFL chose not to honor the contract, BFL then resold the goods in question at a higher price (via more pre-orders). Pretty cut and dry. BFL's choices are to: arrange for the purchased amount of GH/s to appear in Xian's mailbox, re-instate his order, or pay the going market price for an early BFL order at the time of the cancellation.