Here's the site plan for the second tower. Just to the right of the text box that indicates a 695' height is the "condo lobby". A 55-story condo/hotel project would be around the same height as the Austonion and Independent.
The site plan status is "CC Pending." Based on what usually happens, it will change to "CC Approved" in a few days; then about a week later it will go "In Review." Within a week or so of going "In Review" an attachment will be added that includes some basic info about the building(s). So in two to three weeks we should have some good info about this.
ftp://ftp.ci.austin.tx.us/ATD_AULCC/...avis_PLANS.pdf