The site development plans were posted for the building, and it shows the elevations. The highest portion of the roof is 606 feet and the building will have 52 floors.
At the moment this would be our 3rd tallest, but there are three other buildings in development that would be taller than our current tallest building.
ftp://ftp.ci.austin.tx.us/ATD_AULCC/...SS_PLAN_02.pdf