It would be great if the IDE fills the new window with such content to speed up starting a new sketch.
Preferably this text is read from a file called CTRLN.pde or new.pde or so. This way the user can patch the default content easily.
This morning I started some fiddling with AutoHotKey.exe to get something similar done, it has a lot of possibilities - see AHK-code below -
Works quite well on windows, but it won't on linux or Mac-OS - That's why I propose/prefer a build in solution.
AutoHotKey script for WINDOWS-a key combination to generate a minimum sketch
There is a basic start-up sketch in the file/examples/Basics/BareMinimum that you can edit to include the serial commands you want to default with. Then when you wish to start a new sketch, you can just open that file and then do a save as with the new name of your sketch and off you go. So not a single hot key, but it will save you keystrokes on starting a new sketch.
There is, actually, a way to do what you're suggesting. I forget if it was an ide mod or what but "template" was part of what it was called. sorry to be vague but have a good hard google around and maybe you'll find it.
If you create a sketch (or move BareMinimum) to the /examples root directory, then it's only one more button click to open up the example than new sketch (2 if you use ctrl+n)