Hello
I found Unitron 2.1.5, and I’m sharing the link for Unity 4.3.x users. I don’t like monodevelop, so I’ll stay with this lightweight text editor.
https://mega.co.nz/#!TtY1zTwb!UHvgXyKLGZJ7LTSps6OEgz8M_jtGyFoIfO6VcqA_hCw
I don’t know if this is legal or not, it’s just to help the unity developers.
You can just download a previous version of Unity that contains Unitron. I would not recommend downloading from unknown sources.
–Eric
I know, but I can’t download 1.2gb for a tool of 1.7mb :). I think that Unity should provide the Unitron download link on archive downloads. That will be very useful for non-Monodevelop users.
Why not Visual Studio Express? It’s free. 
Doesn’t run on Macs, which is kind of the point of this topic…
–Eric
Unitron was Mac only? Learn new thing everyday.