I run MAME on an HD Sony Bravia 50inch LCD - old MAME is fine, but newer MAMEs suffer from sound jumping in many games.

I found this on another site posted by someone calling himself 'FatTrucker': "Versions prior to 112 using the synchrefresh option could throttle mame back to update at the monitors refresh rate. It solved sound glitching but caused problems with improper emulation with mame having to miss or jump over video frames to maintain the lower refresh rate, so mamedev killed it. Now all games in mame run at their native speed regardless of the system they are running on. The emulation is far more accurate but the tradeoff is that if you aren't running on a CRT or other display that supports 60hz+ you may experience sound and graphic tearing issues."

My question is: are there ANY derivative/non-official MAME builds that address this b!tch of a problem (by making the synching work like it did before)?

Not sure... you could try Cabmame... see the pinned front page topic for the link.

I'm running 129 and the option is still present in my MAME.INI

I think you mean the "sync to monitor refresh" option. It doesn't actually work though - running it on an LCD screen with a stated 60Hz refresh rate (but actually ever-so-slightly less, like almost all LCDs) - the problem is there regardless of what this tickbox is set to. It think it was the 'match game refresh rate' option in older MAMEs that could be unticked and this resulted in perfect sound on a 60hz display.

I don't think MAMEdev would ever put the feature back in - not if it's something that would ruin the 'accuracy' of the emulation (even though it makes it more accurate to our eyes and ears I might add)...

But so, so, many other users must be blighted by this same problem, with the prevalence of LCD displays today - not many PC users are still on 17'' or 19'' CRTs... The sound still skips even on my £1200 30'' Apple Cinema Display and outside of crazy 200Hz and above 1080p displays, it's going to happen to almost everyone running a PC on a modern display.

Therefore, I would assume one of the teams/people making unofficial builds might realise the significance of this problem and just make it work like it used to in their unofficial version of MAME - If so, which one(s)?

I'm going to try Robert's suggestion of cabMAME and I'll report back.

I downloaded cabMAME and put some roms in that I knew used to stutter in the newish MAMEs and just listened to their sound carefully. As far as I could tell, it might be less noticeable (I wasn't sure if I heard it a couple of times or if I was imagining it after being so used to the sounds from these games missing a beat)

So far, it SEEMS to be an improvement, but I don't want to jump in and say it's fixed until I've used it a bit more...

However I can't really do that yet - I'm having trouble getting this version to run full-screen - stretched to fit the display. When I run a game (not windowed) the image is very small in the middle of the screen. I've tried a lot of combinations of different options to stretch it/zoom in and nothing has worked, plus it's also locked in a widesceen aspect ratio. Any ideas how you get cabMAME running full-size with a 4:3 aspect ratio?

I just tried another version of MAMEUI (official 0.129) and using the exact same options, it blows the image up to full-size and with the correct aspect ratio. What is the problem with cabMAME? It doesn't seem to listen to applied settings...