I think the reason you can't see it on the market yet is because the DriodX hasn't been sactioned yet. There actually could be a couple reasons why the Slingplayer Mobile (SPM) for Android isn't showing up for you in the Google Andriod Market Place. This is because SPM is marked as a paid, copy-protected application. Google uses filters in the Android Mariet to manage access based on sanctioned country, rom, and phone combinations.
Only a small subset of countries have the ability to buy Andriod applications. The country is determined by the SIM in your mobile device not by physical location. So, you could get around Google's filter by using a pre-paid SIM from one of the supported country.
The other filter is due to the application being copy protected. Google will govern your access based on the "/system/build.prop" file. If it is sanctioned, then Google will have its fingerprint saved it in their database. This can prevent certain phone/ROM combination and rooted access from seeing any copy-protected applications within the Andriod Market.
The following link best describes the issue and possible workarounds (http://androidforums.com/samsung-galaxy-spica/98024-protected-app-market-fix-tutorial-build-prop.html).
When you get it worked out, then you'll be able to use google's goggles with this picture.
Or this link (market://details?id=com.slingmedia.slingPlayer)