He's released Dosbox for OpenDingux with sources, give the guy a break.
Just because he learned we made our own Dosbox port for A320/GCW (not yet released, but videos were presented). We tried to get the sources of Dosbox from Slaanesh since 2010. We've been asking, begging, threatening, bribing, but nothing helped. So then d_smagin had to re-do the entire work from scratch, mainly fixing and expanding the psp dynarec core, which was a lot of hard work. Now when d_smagin presented his progress, suddenly Slaanesh decided to release his work.
So yea, I wouldn't count on a change of heart, he won't release the MAME4ALL sources, unless someone makes his own port. Then he will release his code a day before, just so he can be the center of attention.
Really, that guy's impossible.