I'd go with making a scroll or flat peg head an option. Another option would be to have some sort of geared tuner available.
Personally I prefer a flat peg head with guitar type tuners (2 to a side) over a closed bottom scroll with any type of tuner. Since my hands haven't aged well, I just can't handle the wooden pegs at all. Even the zither pin type tuners I have on a couple of instruments are almost impossible to accurately tune any more.
Leaving your options open gives you a wider customer base.