I had my boat out the other day, looking for my dive flag, that went sailing across from Windy Point towards the yacht club, to no avail. I think the sailboats got it. In any event, the deepest depth I saw on the finder was in the 125' range. I have heard it is deeper in places.
As mentioned in Windy Point dive condition reports, people have been down in the 123' range, where it seems to open up/flatten out like it is the river bed. I have heard that the Oasis wall is one of the best places, which goes down to 130'+ (at this moment, that could be 100') -- Lake Travis Charters does trips over there, I have not yet had the pleasure.
So, for a shore dive, the folks have been talking on the board about diving the Mansfield Dam,
http://www.co.travis.tx.us/tnr/parks/mansfield_dam.asp exploring areas not usually accessible to normal divers, you can get to that by going to the Mansfield Dam park, the other two easy options are Windy Point Park (private) and Windy Point (public)
http://www.co.travis.tx.us/tnr/parks/bob_wentz.asp Bob Wentz park. The drop off is ok there, you can park by (not past) the cones at Bob Wentz, carry your gear to shore near the public porta potties and walk down to the beach entry, follow the bare path/spot down to the water, enter there, and drop to about 50' and you will find the scoreboard. Head north toward Windy Point (private)
http://www.windypointpark.com/ to find stuff like the large sailboat2, some old standing trees, and so on. Large Sailboat 2 is at 50' to 60'
A little more North of sailboat 2, I found a platform at 50' and a little farther is what must be the Pinto, though you can hardly tell it is a car at all at this point, typical Ford rust. Along the way there are several drop offs and grottos and all and all an enjoyable dive. I'm not much interested in doing any particularly deep dives in Travis, unless there is a compelling reason to do so.
One guy, claims to have lost a keel, motor and battery at 80' which might be interesting that is somewhere within a mile of the damn. I talked to him, and offered to go out with him and pinpoint the location, however he never called me back. Instead he put a new craiglist ad a month later, so I don't know. I couldn't cross reference the co-ordinates he posted online, if we could pinpoint a location and get a few folks together to do a search, it might be fun. There is a small reward.
Also, as a side note, there is a rock wall, (piled rocks) built before the lake was flooded, which surrounds West beach marina, there are several anchors, and so on to look at there, but the depth will be minimal. Shore entry is possible there, I have a boat there, so I have the gate code.
With dive conditions, and water depths where they are, from my knowledge, that's probably all the options, except to take the boat trip.