formfactor is the current method supported in OE-Core for representing differences in machine display/input characteristics, however it seems only queryable at runtime since its files are not written into the sysroot. If we could change it to stage to the sysroot, the data could be queried at least at packaging time in other recipes that depend on formfactor (for example, where you want to provide a machine-specific package that installs pixmaps of the appropriate size for a display on a particular device without having to install more files than necessary.)
I've not seen huge demand for this since I proposed it and I've not had time to implement it. If there is a need for it please let us know and we can reopen.