In other cars we've had there has always been a grab handle above the passenger door. Not that I'm a wild driver, but my wife has wished for one in the smart also.
I stopped at an auto wrecker, one where they let you wander about and remove stuff on your own, and got a grab handle from something, might have been a Ford, that was pretty much the identical color to the interior plastic in the smart. Less than $5. I chose a "flexible" handle, but they also come in solid or folding styles. I thought the flexible would offer more mounting possibilities.
After pondering lots of locations I chose the one shown in the photos below. It doesn't interfere with getting in or out, or with visibility. The local smart service manager told me there are no wires in this location. I hope that's true.
There is, in some locations, quite a bit of space between the moulding and the frame inside. Not wanting to put a bending strain on long screws, I chose to mount it so the pull is straight down. The screw length shown is what was required to reach at least a quarter inch into the metal frame, and is very sturdy.
The mounting should be done as far outboard, toward the door, as possible to be sure the drilled hole goes into the frame, not just through the moulding and into dead space.
I like it, and so does my wife.
The handle and screws it came with, which I didn't use.
The self-tapping screws I used.
The final install.