Drupal7 REST webservices API KEY vs OAUTH two-legged authentication for clientside JS consumer library
The solution came from Kyle Browning (thanks!) - the current dev version of services 7.x-3.x-dev has support for the following OAuth authentications methods:


None, OAuth authentication will be disabled by default
Unsigned with consumer key
Consumer Key, also known as 2-legged OAuth
Consumer key and access token, also known as 3-legged OAuth


With this version I ended up using the consumer key for the client libraries as identification token for applications.