Almost completed,
single item and list of items are 100%. I just have to complete single category and list of categories (easy). I have suspended for a couple of week to publish the hello world plugin and the sample mobile app /you can download from this site). Tomorrow I will work to finish this module and start others, so I hope to release it this week end.

Kind regards,
Luigi

Just released for Joomla 3:

www.selfget.com/downloads/file/34-plg-jbackend-k2-j30.html

Tomorrow I will publish the documentation and the version for Joomla 2.

Kind regards,
Luigi

No,
at the moment there are the same "features" of the content module:

www.selfget.com/documentation/jbackend-joomla30/content-module-api.html

The reason is almost simple. Each function of each module should act the same way of its extension (in this case, k2). This is not so easy due to lack of internal API to call and code complexity. This requires a selection of functions to implement (usually, the most used, as example, to build a mobile app). Otherwise it would be necessary for each module the same effort required for its extension.

The image upload, as example, is a content editor feature, and is not so commonly required. But this doesn't mean it could be implemented in the next version. Is just a matter of "priorities"... hope this is clear.

Kind regards,
Luigi