problem with engraving "breath" tones

[Eric Flesher]

I have a score that involves numerous passages of wind instruments making pure
breath (i.e. non-pitched) sounds; as per Kurt Stone, these should be indicated
on a single tablature line above the staff with circular noteheads. These
noteheads are unusual in that they are centered on the stem (i.e. the stem goes
through the center of the circle), with the stem protruding about a half a space
above/below the notehead. A simple example can be found here:

http://www.ericflesher.com/scores/example/air.jpg

What I'm looking for is a solution that will allow me to introduce and remove
this tablature staff at will, including in the middle of the bar; I would
further like to be able to import a pre-existing symbol for this notehead, as it
does not appear that the Feta font has such a symbol. Any ideas? 

Many thanks in advance.
EF

P.S. I have tried the following work-arounds, neither are terribly good:

1. Creating a 6-line staff, with the top line moved up 2 spaces to simulate a
separate tablature line. Advantage: ease of getting the breath pitches onto the
staff. Disadvantage: Solution does not work if leger-line pitches occur while
this 6-line staff is in effect.

2. Creating a separate, 1-line staff for the tablature pitches. Advantage: Can
easily accommodate leger-line pitches from (1) above, without placing these
above the tablature staff. Disadvantage: Space between staves must be adjusted;
may encounter problems in introducing/hiding staff mid-measure and/or 
mid-system.

3. Creating a line with \draw-line under \markup for the tablature staff.
Advantage: None I can see so far. Disadvantages: The line will move to avoid
collisions, thus making it difficult (if not impossible) to place noteheads on
the line. Insufficient documentation (IMO) on the destination arguments taken by
\draw-line, thus making the placement of such line a lengthy trial-and-error
process.