Was able to get an answer as to why a lot of Viva's releases seem to be out of stock. Given the "difficult" market for original DVDs since mid-2004, they've been cutting back on volume imports. Apparently demand really spikes upwards during sale weekends, but they lose money on every copy sold. In other words, the distributors probably support these events just to reduce their inventory levels.
Viva's new strategy of bringing in smaller quantities and relying on reorders protects their interests, but it also creates an environment where DVD collectors will have to consider buying their DVDs at full price. Waiting for a sale doesn't assure that you'll be able to pick up copies at a discount. Heck you may not be able to find copies at all! Kingdom of Heaven, Day After Tomorrow, and The Incredibles are completely out of stock even at the Viva warehouse so no copies were available this weekend. SW Episode 3 and Fantastic 4 were highly sought after but there weren't enough copies to go around. Astro Podium claims they had less than 50 copies of SW E3, and nearly all of them were reserved Thursday night.