By the way, Hol, I found an updated version of the THEESA study, from 2009. It shows adventure game market share grown to 5.3%!
http://www.theesa.com/facts/pdfs/ESA_EF_2009.pdf
This is actually very good, even such popular genre as strategy has only 6.2% and RPG, another popular genre, only 5.2%!
It appears that the market is certainly there...
ps. How can I turn on reply notifications, so that I get an email everytime somebody replies?