Cubase 8 's Retina Display Support could be enabled by modifying plists inside its app bundle.
Use Textwrangler to open the following file:
“/Applications/Cubase 8/Contents/info.plist”
find
<key>NSHighResolutionCapable</key>
<false/>
modify that part into:
<key>NSHighResolutionCapable</key>
<true/>
Save that plist, restart your mac.
Screenshot: https://app.box.com/s/3dsqv361b52jnt79f56b