I asked this question about a month ago. The consensus seems to be a bra under the trisuit is the only real option. I think for me that will definitely true. I wore a tri top to spin class one day and it didn't have enough support for a standing run, so i can only imagine how uncomfortable an actual run would be. Do a search on boobage and a couple of good threads will come up.
Brina
"Truth goes through three stages: first it is ridiculed; then violently opposed; finally, it’s accepted as being self-evident." Schopenhauer