Even though Dell has basically left its Streak 5 and Streak 7 users in the dust, luckily we still have 3rd party software developers and accessory manufacturers who care about us.
Above is an adapter for the 30 pin connector that the Streak 5 and Streak 7 use. It plugs into the Streak itself (obviously) and you can plug a miniUSB cable into the adapter. This remedies the issue of the Streak line of tablets being proprietary, but the dongle is still a nuisance. It's manufactured sold by a Chinese manufacturer seller by the name of Taobao, but that company only ships in China.
The second accessory to come out of China is the OTG cable for the Streak 5, which enables you to directly plug in USB devices without having to make your own cable or use the multimedia dock, which can certainly be an expensive venture. Unfortunately, this seller isn't ready to sell the cables to consumers just yet; they're only selling in wholesale quantities of 100 or more.
Still, it's nice to see some more companies realize the potential that the Streak line still has.
[xda-developers 1, 2] Thanks, Themanii!