On Sat, 25 Jun 2011 09:46:05 +0100, Michael Everson <[log in to unmask]>

>On 25 Jun 2011, at 04:01, And Rosta wrote:
>> And if it can be written in a single continuous line, what is impractical
about boustrophedon; what better methods could there be?
>Your scheme is damned from the outset by your definition that text can be
written in a single continuous line. Boustrophedon is impractical because it
can't be read. That's why it never survives.

As one data point we might look to Tapissary , especially
Travis decided to change it to boustrophedon in 1996, and since then, AIUI
under continuous usage, the two directions have only diverged. 
Right-to-left ("sunrise") generally induces changes in the original shapes
which left-to-right ("sunset") has retained; among other changes, a number
of glyphs develop strokes as long as the whole line of text for the others
to perch on.  There are syntactic changes as well.  

Admittedly the normal pressures on nat-scripts are not the ones in force
here; this was all intentionally cultivated if not imposed.  Still, one
could at least ask Travis whether Tapissary is readable to him.