This seems like a good idea, but it's actually a trap. Now developers will be even more empowered than usual to set your perfectly legitimate, fully characterized bug to the "Incomplete" state on Launchpad. Example:
"Reporter, did you try vanilla 2.6.68-rc7? State => Incomplete"
See how easy that was? And considering how prevalent this behavior already is within the Ubuntu project, there's really no need to contribute by expanding the universe of possible kernel permutations. Recently an Ubuntu developer set my bug to incomplete after asking if I'd tried the kernel.org kernel, without even offering up a link to a package file. This is not a good way to run the project, and Canonical or somebody should get a handle on Launchpad workflow and policy before exacerbating the problem in this way.