I might be in minority here, but why does everyone have to do the next (2nd, 3rd, 12th, etc.) in his career? I've been asked the same question about my next career step during interviews and always answered I'm perfectly happy of being a DBA now and don't want to go higher in the corporate ladder. If that is not an expected answer from HR prospective - I couldn't care less. There are enough of challenges and day-to-day problems for DBA to solve to keep your mind sharp and your job satisfying and interesting. And if you feel stuck, move on to another job.
I also agree with previous posters that DBAA functions are better suited for a system architect. Some business folks and even IT managers having difficulties understanding what a DBA is and why they need DBA's, let alone DBAA.