Vertical alignment of text added to notes.

[Steve Lacy]

Hi, I'm engraving some simple music for beginning violin students who are learning to read music. 

I would prefer if the text added to notes were vertically aligned on each line, but by default they are quite jagged: 

(http://lilybin.com/to3r9r/3) 

I had thought about using \lyricsmode for this purpose, but it seems like the wrong solution to this problem.  I would prefer to be able to specify a fixed-veritcal offset from the top of the staff (or top of skyline?) for all special \markup.  Kind of like: 

A = \markup {  <<somehow set vertical position relative to staff or skyline?>>  "A" } 

and then my notes would be 

relative c' { a^\A b^\B } 

Steve