I shared it primarily because it is an open-source UI project managed by Microsoft that has to support an "API" that is cross-platform, but it also meets this p

I shared it primarily because it is an open-source UI project managed by Microsoft that has to support an "API" that is cross-platform, but it also meets this portion of your original criteria: > as long as you can host the language a given UI framework is built in, you can use it to create UI elements in whatever platform you want (The work has already been done to host React/JavaScript cross-platform alongside .NET: see Edge.js http://tjanczuk.github.io/edge/ http://tjanczuk.github.io/edge/ previously mentioned elsewhere in this thread. http://www.hanselman.com/blog/ItsJustASoftwareIssueEdgejsBringsNodeAndNETTogetherOnThreePlatforms.aspx http://www.hanselman.com/blog/ItsJustASoftwareIssueEdgejsBri...) As an aside, I recommend you include some details summarizing reasons for rejecting existing solutions when initiating future discussions so all participants can begin on the same page.