OP - I haven't read all the posts yet but I have a yappy little dog (aptly nicknamed "The Barkinator") so have been on the other side of the barking dog issue. My suggestions would be to first talk to the neighbors so that they are aware that it is a problem as they may not even know it is. If you aren't comfortable doing that and your HOA won't do it for you (make the dogs owners know it's a problem) then contact your local cities animal control officer. Many cities, mine included, have a "nuisance animal" ordinance which includes barking dog, and they will cite and fine your neighbor - usually with a warning first and ticket and possible court appearance next. This happened to me and it not only made me aware of The Barkinator's barking while I was gone (have a house with a dog door to the back yard) but forced me to correct it ... well try to correct it as it is still a problem.... if I wouldn't do it myself (I would have if the neighbors had told me first).
Here is a ordinance for my city:
Barking Dogs
It is unlawful to allow an animal to disturb any person by audible sound. First complaints are issued a warning; subsequent complaints within one year can result in a summons to court. The city's barking dog ordinance can be found in the City Code under Title VI (6-7-7).
I've found my own way to deal with The Barkinator but probably won't work for you:
"Listen, and understand. That Barkinator is out there. It can't be bargained with. It can't be reasoned with. It doesn't feel pity, or remorse, or fear. And it absolutely will not stop, ever, until you..." give it treats.