Lately I've been building a class of super-cheap Civilian ships, classed as "Exploration Vessels". They carry nothing but one high-performance Civilian engine, a one-hull-square active sensor, a one-hull-square EM (or Thermal) sensor, and minimal life support and fuel. No armor, shields or weapons, no Geo- or Grav- sensors.
They can be built (and therefore replaced) in just a few months in any Civilian shipyard, cost next to nothing in credits and minerals, and their job is to be the first ship through any newly-discovered jump point and to quickly visit every signifigant body in the system and then return home to report.
The active sensor is carried simply to give away their position and draw out any hostiles in the system. I lose quite a few of them... but because they flush out any hostiles before I send in my Geo- and Grav- ships, I very rarely lose a more valuable ship.