Yamaha 'Registration' files already support saving transpose settings and just about every other setting on the keyboard, including calling up lyric/chord text files too.
The big irritation lies with not being able to call up Registration files from within Music Finder, where your entire songtitle listing can be stored.

This leads to my Korg Songbook question: From Songbook, is it possible optionally call up from your entire song repertoire: either alphabetically, by genre, by artist, etc?

The actual 'viewable' Tyros 4 screen area is still substantially larger, brighter, and more colorfully vivid than the Pa2X/3X and in fact for lyric/text display, @ 16 pt font size: each page supports 64 characters per line and 20 lines per page. Regrettably, the Pa2X/3x's display supports far fewer text characters per line and lines per page. As far as a touch screen goes, until the keyboard manufacturers implement the 'outdoor sunlight viewable' type of touchscreens currently available for the iPad, I'm not interested.