The next release will be just after MAME 0.155 comes out... whenever that is.
A lot of people have kindly pointed me to various desirable NeoGeo and PGM hacks, however most of them haven't been included because they don't work.
NeoGeo - it seems that most hacks originate from China, and they develop on hacked emulators such as Winkawaks Plus. The 68000 core in these emulators do not raise an exception when unaligned addresses are referenced, but the MAME 68000 does complain, usually resulting in a complete failure to start, or a crash in a particular sequence, such as a special move. So, this rules out the inclusion of those particular games.
PGM - suffers from a similar problem, usually causing the game to freeze and the screen to be filled with a register dump. Also, there is unemulated protection in many hacks. A PGM expert might be able to sort out the protection issues.
Also please note that I'll be experimenting with using a dedicated download host this time around, instead of from my site. If there's any problems, please let me know.