hrmm you know... i like your idea. I'm going to think of how I would do such a thing. Because it would have to be alternating...
the logic of snaps and waves, is that there are two accounts who start new posts, and then snaps are comments underneath the post (replies). So, to get the latest snap or wave, you find the last post made by these accounts and display the replies in order (newest first).
To do what you say, you would have to create a custom stream that would look at both account's replies at the same time, and order the replies in order, regardless of who they are replying to.
/me thinking hard
Haha. Thanks! You just can't keep up with all the different feeds. If one tool could add them all together you would get more unity. And it wouldn't matter which front-end people use to microblog.
But I don't know if it is technically possible.