Regarding heat removal could you offer options depending on what the persons most common use for the speaker is? One thing I realize is that you don't have a "typical" user for some of your designs and what is "best" for one person isn't for the next. Adding some noise might be a tradeoff worth making if it provides much better cooling for some people. Having test numbers to compare options would help people make their choices.

I like the idea of quick access panels over removable assemblies. Removable assemblies open up opportunities for vibration, poor fit if building isn't percise, and loosening up over time.

Enjoy your Sunday.

Grant.