Amazon is seemingly set to unleash an update to its Kindle ebook readers across the board, as evidenced by the fact that the entire e-ink line is either discounted or discontinued. While the entry-level Kindle is still in supply, the $99 Kindle Touch isn't shipping for 3-5 days, while the $139 version that comes without ads is simply no longer available. The $149 Kindle Touch 3G is also unavailable, and the larger Kindle DX was discounted by $110 on Friday. Supply constraints and discounts like these aren't typical for the Kindle line, except in the instances where Amazon is set to refresh the line. Word on the street is that we'll see a Kindle event sometime in the next week or two that'll highlight updated models.