I've only been into this hobby for 4 months. I've bottled 12 batches and have only encountered a flat beer with my imperial IPA. I have the sediment on the bottom of the bottle (I assume the DANSTAR BRY-97 Amerocan West Coast yeast and nothing more) and I can see it get kicked up when I swirl. I have bottled other beers that are carbonated, but this batch won't carb up.
I am going to rehydrate Red Star Champagne yeast tonight and pitch into my Imperial Stout. I'm hoping the yeast won't eat too much simple sugars in the secondary and only chow down on the priming sugar for bottling and priming.