When I was messing round with lr-dosbox about a year ago you could control the mouse using the gamepad analog stick. I think this is exactly what you are looking for.
@mitu @Efriim :
memsize=32 (did at my 64) does go in the dosbox.conf, sorry to confuse them. They look similar, I don't type very well.
i think that one help .
but im not sure lol :)