Sweet. Nice to hear there's thought taking place concerning an eventual 3.0 some day :)

This looks promising - exactly what I was thinking was possible for authoring a menu, or set of menus (you mentioned a couple slideshows...) - - - http://forum.doom9.org/showthread.php?p=1119634#post1119634

Seems like it is indeed possible to simply create a "fake" project, then throw in your rendered m2ts file(s), tweak a couple things, and it should work as expected.

Not sure if chapters would come across as functional, but it's worth a shot.(see: http://www.afterdawn.com/guides/archive/afterdawn_blu-ray_encoding_tutorial_lesson_3-chapter_points_and_bitrate.cfm)

Subtitles may also need to be 'rendered' with something like this - http://www.afterdawn.com/guides/archive/afterdawn_blu-ray_encoding_tutorial_lesson_8-convert_text_subtitles_to_images.cfm

I'd be willing to give this a try, making a 'fake' project, trying the 2.1 m2ts, adding a slideshow, but I don't know when I'll have time. Crazy busy month ahead.