If I wanted to collect Disney shorts, I'd make a list first. Many Disney blu releases of full-length films come with one or two shorts on them. So I'd start with those. Thankfully, some of the Disney fans on the blu-ray.com forums have made pretty great lists:
Shorts by type:
http://forum.blu-ray.com/showpost.php?p=6037173&postcount=1
Shorts by blu-ray release order:
http://forum.blu-ray.com/showpost.php?p=6037197&postcount=2
Slightly more updated shorts by original release year, along with the blu-ray release they were attached to:
http://forum.blu-ray.com/showpost.php?p=8795285&postcount=398
But after that, the Treasures line is in fact the last home release for most of the shorts, and it seems unlikely they will release many of them on Blu-Ray (the Treasures DVD releases were somewhat improbable themselves, unprofitable by the end, and happened at least partially because of Leonard Matlin pushing the issue). I'd hope for streaming, personally.