FWIW: Technically Merrimack is a MA school
I think you have a mix of reasons why NH players don't play/stay in NH. Some has to do with ability - as LJ mentions the better players have to play out of state since Dartmouth is the only option and you have to have high "academic requirements" to get in there. If you are a better player, then you've probably done the Southern summer tournament circuit as a 16-18 yr old with one of the 2 or 3 competitive travel teams - none based in NH. I can think of a few of the top players of the previous years that are now in ACC schools or for 2 of them playing for the Yankees. Another part is "being recruited" - unless you have a good HS coach or are already well known, my experience was that it's up to yourself to make your child known to the local schools. For my son, none of the local schools were appealing to him academically - baseball wise the only one that he was interested in quickly brushed him off. It's worked out for him because as a freshman in a D3 school he's one of the 4 starting pitchers.
Beyond that those that love baseball may not like the cold weather and if you've played here long enough you perhaps would like to see what it's like to be able to play baseball outdoors more than 7 months a year!
To answer your other question about "a" resource - other than perhaps Google or being savvy enough to create a program that will visit the website of each college baseball team to cull the data off the roster, I'm not sure there is a single resource that lists all the NH players playing college ball. Although, any that have played the last few years in the Showcase League will have their college choice listed on that website (http://showcaseleague.com/?page_id=631).
