One of the reasons Dell Streak users were so pleased to learn that the device's "proprietary" connector was actually PDMI was the prospect of finding cheaper cables. The official USB Charge and Sync Cable for Dell Streak retails for $19.99, which is pretty steep compared to the cost of the microUSB cables that most Android phones use for charging and syncing.
Unfortunately, tracking down a compatible cable hasn't been very easy. Not until recently, anyway.
A 6-foot cable from Hong Kong surfaced on eBay last month (about 6 months after the PDMI identification), where it's still selling for about $9 shipped, and now there's another option: a shorter 2.6-foot cable for $4.40 shipped from DealExtreme. Amazing, yes, but the bargain-basement pricing doesn't stop there! If you buy 3-4 cables, the shipped price drops to $3.69 each; 5-9 cables, $3.59 apiece; and 10+ cables, $3.49 each.
[DealExtreme] Thanks, nisshi9!