16" needles are point-to-point. I actually don't think the interchangeables come that small since the needles themselves take up most of the length.
The 16" fixed needles have a shorter tip than the interchangeable tips to give you more leeway. The KnitPicks fixed 16" needles are pretty good and reasonably priced.
The shortest needle I've every used was 12" but it was like knitting with toothpicks attached by a cable.