Over the last few years I had come to believe that the roasting process for bold coffees removed caffeine from the beans resulting in a lower caffeine content than compared to a light roasted coffee. I got this idea from Good Eats with Alton brown. Here's the clip where the master roaster makes this point.
However, yesterday's On Point w/ Tom Ashbrook had on a coffee expert that made the opposite claim. Also, comments the page have pointed to sources describing the inconsistency of caffeine levels: Caffeine content by roast level and Does dark roast coffee have less caffeine than light roast?
Searching around on .edu sites I find charts that seem to support the idea that bolder coffees contain more caffeine. The charts show smaller amounts of bold coffee (2-4oz) contain the same amount of caffeine as larger amounts of light roasted coffee (6oz). So, obviously, typical consumption amounts play a role in how much caffeine will be ingested.
In the end, I'd like a definitive answer to this question: after roasting which bean contains more caffeine or is the difference negligible? And/or does the brewing method significantly alter the caffeine content?