In detailed physiology/cellular biology level how does the carotid
baroreceptor convert mechanical stretch due to changes of blood
pressure in the carotid artery into a signal that is transmitted to
the brainstem .i.e. what are the cellular mechanisms that govern how
action potentials are generated by stretching the artery wall?

I really want an explaination on the cellular level not something like
stretch causes increase in firing rate in carotid nerve. To date I've
read basic physiology graduate level books which all brush over the
mechanism like my explaination here.

Also I would like suggested titles of books that may contain such info
- and list of some of the most important people in this area of
physiology

Thanks :)

This still appears to be an area of current research and theory.
Best candidates for actual generation of the action potential are
mechanosensitive ion channels.
Some links to research papers:

Non?Voltage-Gated Ca2+ Influx Through Mechanosensitive Ion Channels in
Aortic Baroreceptor Neurons. Margaret J. Sullivan, Ram V. Sharma, Ruth
E. Wachtel, Mark W. Chapleau, Laurie J. Waite, Ramesh C. Bhalla, ,
Francois M. Abboud. Circulation Research. 1997;80:861-867.
http://circres.ahajournals.org/cgi/content/full/80/6/861

Mechanosensitive ion channels in putative aortic baroreceptor neurons 
Shane Kraske, J. Thomas Cunningham, George Hajduczok, Mark W.
Chapleau, Francois M. Abboud, and Ruth E. Wachte. Am J Physiol Heart
Circ Physiol 275: H1497-H1501, 1998.
http://ajpheart.physiology.org/cgi/content/full/275/4/H1497

Mechanosensitive currents in putative aortic baroreceptor neurons in vitro
J. T. Cunningham, R. E. Wachtel and F. M. Abboud. J Neurophysiol 73:
2094-2098, 1995.
http://jn.physiology.org/cgi/content/abstract/73/5/2094

there is some overview of concepts and references here:
Molecular Basis of Mechanotransduction in Living Cells. Owen P. Hamill
and Boris Martinac. Physiological Reviews, Vol. 81, No. 2, April 2001,
pp. 685-740
http://physrev.physiology.org/cgi/content/full/81/2/685

here's an animal paper on the electron microscopic features of the
baroreceptor relevant to mechanical potentiation of pressure
differences in the area of the sensory nerve endings:
Electron microscopic structure and innervation of the carotid
baroreceptor region in the rock hyrax (Procavia capensis). Kimani, JK.
J Morphol. 1992 Jun;212(3):201-11.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1507237&dopt=Abstract

apart from the authors of these papers and their significant
references, I also found this
http://www.metrohealthresearch.org/baroreceptor.html