blueMSX-libretro
source http://sourceforge.net/p/bluemsx/code/HEAD/tree/trunk/blueMSX/Make/blueMSXlite/ svn://svn.code.sf.net/p/bluemsx/code/trunk
this core requires the two folders named Machines/ and Databases/ from standalone blueMSX copied inside your frontend's system directory.
you can get these from the official windows standalone version of bluemsx (http://www.bluemsx.com/) or any other binary package.