I would agree that 30 seconds is getting towards the upper end of what you can pull off. But I believe that it can be done, if you manage your body language, hand gestures, facial expressions, etc. properly. Now if somebody stood there for 30 seconds doing the "blank expression" thing, then yeah, it's starting to get awkward for everyone.
Anyway, here's a thought: make a game out of it. Next time you're speaking in a group setting and this comes up, (when it's a situation where nothing of substance is at stake), try and see how long a pause you can engineer before somebody starts doing the "intentional cough" thing, or says "are you OK?" or whatever. Maybe do it a few times and see what you can work up to. Maybe 30 seconds is a bit more than can be managed. And to be fair, it's probably context / audience dependent to some degree as well.
The problem is not so much the uncomfortableness of it, but if you stop speaking for 30secs half your audience will be already fidgeting their magic infinte scroll glass slabs TM to try and entertain their minds / fill the void...
Anyway, here's a thought: make a game out of it. Next time you're speaking in a group setting and this comes up, (when it's a situation where nothing of substance is at stake), try and see how long a pause you can engineer before somebody starts doing the "intentional cough" thing, or says "are you OK?" or whatever. Maybe do it a few times and see what you can work up to. Maybe 30 seconds is a bit more than can be managed. And to be fair, it's probably context / audience dependent to some degree as well.