I often work on the go on relatively small laptop screens, and having a ~70% transparency editing window allows me to keep an eye on consoles etc. running in the background. I’ve just started using the program but I looked through all the preferences and didn’t see a way to set window alpha, does this exist yet in ST2? Thanks!

Doesn’t exist.
People want it though: sublimetext.userecho.com/topic/5 … eme-level/

Ah, that’s too bad. I guess I’ll have to stick with my rusty old TextMate for now!

If you mean transparency like this http://i.imgur.com/vg7lO.png then there are several utilities that allow you to set window transparency. I use a program called WindowFX ($10) that makes DWM behave a little more like Compiz, but I’m sure there are free alternates for Windows users. Since you mentioned TextMate I assume you’re on OSX instead, but a quick google search turned up what appears to be a similar program: http://infinite-labs.net/afloat/

with Autohotkey this is just one line:

WinSet, Transparent, N, ahk_class PX_WINDOW_CLASS

N is a number between 1-255

http://www.autohotkey.com

(oops, this is for Windows only)

The problem with these solutions is that the text is also made transparent (and thus harder to read). Ideally the background is transparent but the foreground is not.
It’d be cool if you could pick a color to make transparent. Seems like that’d work–just pick the background color and off you go.