Don't have much time but two quick comments:
Application Log on / off: I have been thinking about this one myself. But instead of a check box, I would like a 'log window' option in the menu. That way, it would take up no screen space at all if you don't enable it. Something like: "Tools -> Log Window". The only problem is, I haven't figured out how to pop up a log window on the mac. Every time I tried (using QDialog or QMainWindow), I had problems switching back and forth between the log window and the main window

Any help is appreciated here.
Graphing: yes, it'd be great to have a graphing widget for goxgui. c0inbuster
sent me a beautiful screenshot a while ago, and I love his idea of implementing a PyQt widget using the mentioned
ta-lib. I would definitely not hesitate to integrate it into the main branch. If, on the other hand, the resulting graph looked something like
this (just a random example), I'd probably not be that enthusiastic about it

About the log - I'll take a look into this. I don't have qtdesigner handy.
About graphing - probably matplotlib will be involved, why? Because we need to show data asap. The HTML-based graph can be probably shown using qtwebkit, but it will have lag obviously.
I could make one graph using qt primitives but it will take it's toll of performance too (though not as big as HTML-based).
Another thing I want to implement is orders list, can't yet wrap around the qt signaling framework though...