Most are twins as far as I am aware. The SV650, Gladius, and Hyosung GT650 are all v-twins. The Ninja 650R, Versys, ER6N are parallel twin (all basically the same engine actually). The new Honda 700 is also a parallel twin.
You can't always go by size, though. For example, I believe the VFR800 is a 4 while the BMW F800 series is a parallel twin again. There are also 750cc I4's while the Aprilia Shiver 750 is a v-twin.
VFR800 has V4 VTEC engine, quite unique compared to other 4-cylinder bikes.