There are a few parts of your question that I don't fully understand, but generally I think you need to differentiate the concepts of "Tin Can Content" and an "xAPI LRS".
The xAPI specification is an interoperability communications protocol and does not specify what one typically considers "content". It provides a data model for capturing event based data points, and the web service resources used to store and access records in that data model.
Generally when referring to "content" one means a package (or file) that contains deliverable assets that can be imported and launched via an LMS, which is completely outside of the scope of the xAPI specification. Having said that, at the time of release of the 0.9 specification (then called the Tin Can API) there was also release of a set of guidelines for how xAPI could be integrated with an LMS that had a supporting LRS. Those guidelines define a package (a zip file with a tincan.xml "manifest" file), a launch strategy, and various other details necessary to the import and delivery of content. This is generally what people mean by "Tin Can content" and what the major rapid authoring tools have implemented. Those guidelines can be found here:
https://github.com/RusticiSoftware/launch/blob/master/lms_lrs.md
The first part, the xAPI specification communications protocol is well implemented by TinCan.NET. To my knowledge there aren't any open source implementations in C#/.NET of the latter part, the Tin Can LMS guidelines. (There are plugins for Moodle that enable the functionality.)
Having said all of that those guidelines are not on a specification/standardization path, and in general the cmi5 specification is a big improvement (though young) to them for the typical LMS use case.
Given the volume of requirements for xAPI, Tin Can, cmi5 and their older cousins SCORM/AICC you may want to consider buying support rather than trying to build it. Happy to answer additional questions, here or at [email protected].
