Current state-of-the-art yeast systems use champaigne yeast on sugar suspended in jello. The debate now is whether to put the yeast on the jello by itself, or to add the yeast and also fill the bottle with water to the 'normal' levels.
This limits the availability of sugar to the yeast. The dry method limits the sugar availability too drastically IME. I add water on top of the jello. The jello breaks down quicker, but I get fairly consistant CO2 levels for ~3 weeks.
[EDIT] state-of-the-art is still 'ghetto' in a 2L bottle, but it seems Clamato/V8 bottles have the best (biggest) lids making filling easier. Also, it's much more effective to drill a hole in the lid that is smaller than the airline tubing than it is to build a bulk head to attach the tubing to. Trust me on that last one.