We're not going to engage in too much wild speculation on this piece of information, but there are certainly a few raised eyebrows in Engadget-land right now. Apparently Plastic Logic is no longer offering pre-orders of its QUE proReader, as a tipster of ours discovered while trying to push through his order of the $799.99, 8GB / 3G version of the large-screen device. According to the order page "Pre-orders are sold out. QUE will be available online and in select Barnes & Noble stores this summer." This of course comes on the heels of news that the company would be further delaying the ship date from mid-April to summer related to "fine-tuning" and "enhancing the overall product experience." So our minds aren't exactly at ease, as we're trying to understand why a company wouldn't just caveat pre-orders by letting people know there's been a run on supply -- though it's possible that Plastic Logic is doing separate batches for mail order and in-store, and just needs to pace themselves. We've reached out to the company for comment, and we'll let you know as soon as we hear back.