The onething I have been asked over and over again is about a single button capture start, rather than having to position the mouse over the Record button then click it. Are there any plans for this to be available or being able to create a HotKey for this. The second option would be really good as we could then attach and external button and programme this to the same hotkey.
Hot key for toggling recording on/off is CTRL+Enter by default, you can change that in Preferences > Keyboard.
There is also a listener of Windows Messages that will listen to named commands so you can trigger it from external software.
You can also trigger by sound threshold from the microphone input (See Preferences > Capture > Automation). I think from this last one you could also build a hardware trigger by hooking an Arduino or something directly to the Line In (I haven't tried).