Here's a 6 string guitar banjo that has an interesting past. The fingerboard was marked with two sets of fret slots with rough estimates for positions, and no parallel slots anywhere.

This banjo has an interesting set of tuners, with extra little buttons to pull the string posts out and disengage the wheel gears from the worm gears. When stringing the instrument, you can pull the post and quickly wrap the string around the post to take up the slack. Then you push the post back in to lock the tuner, and finish tuning up with the gear.

Since these photos were taken, I've put a new fingerboard on the neck.