I find I'm significantly slower with a trackpad so I'm still using a mouse, but one thing I have been considering is grabbing a trackpad and putting it to the left of the keyboard (as a right-hander) and using it for general scrolling and pointing, then using a mouse on the right for when more accurate mousing is required.
That'd mostly solve the mouse being too far away issue if I were to use the Microsoft Surface Ergo. Do you have any issues with the trackpad that you haven't had with a mouse in the past?
My other option would be just to give up and get an apple keyboard. When you were using it, did you miss the keyboard being split - any RSI or comfort issues?
