I’ve heard of some guy doing Rails on twitch every monday or something, but I couldn’t find him. The idea is definitely interesting, but the question is what’s your end goal? I wouldn’t expect significant earnings and a big audience but I can imagine it would be interesting to some people (me included).
If you go through with the idea, I would suggest you to record the streams and put them on Youtube, it’s a good way to advertise for free. You could also find other people who would be interested and know different programming languages and technologies and share the channel with them. For example you could do monday/friday on Rails/JS (just an example, I don’t really know what you plan on streaming) and have someone do Node.js or ASP.NET (again, just random examples) on Wednesdays or Saturdays. That way you could increase the popularity of your channel. You could also have ‘guest coders’, semi-famous people in the coding world that would like to share some knowledge and good practice with us.
All in all I think it’s a great idea, but like any channel you have to be prepared to put in some time without results, you can expect streaming for a very small audience for quite some time (weeks/months) before you accomplish anything.
And probably the most important thing is, do you have knowledge worth sharing and would the average viewer gain something from watching your streams?