Daala uses wavelets in a few areas, but is largely a lapped DCT based codec. It's not especially suited for producing scalable bitstreams, at least not much more than any other codec. There's little demand for it right now, so we don't plan to include it as a feature.
However, if you have some interesting application of it, feel free to let us know!
This isn't my direct area of expertise, so I apologize in advance if I am incorrect about anything.
Video streaming suffers from unstable connections, and varied throughputs. Some home connections can support high fidelity 1080p and others can just manage visibly degraded 480p.
Right now, either you have to store each resolution separately (which can be costly, esp. at 3x redundancy and esp. if your average video is only going to be watched a few hundred times e.g. YouTube), or you have to transcode on-the-fly, which is expensive for any sort of good compression rate.
As we move forward, p2p streaming is likely to be a lot more dominant. There are a few services already out there and a few more in development that have a lot of promise. P2p settings are even more sensitive to transcoding costs, as you'd rather have peers uploading in high parallelism, meaning each one would need to be transcoding.
I do believe that scalable bitstreams will be important, as they solve a lot of the problems.
However, if you have some interesting application of it, feel free to let us know!