The Tech_Requirement tag (for the hulls that have one) is in GC2Types.xml. Just delete the line to mod out the requirement. Here's an example hull:
< Hull Name="TinyHull0" >
< DisplayName >Tiny< /DisplayName >
< Description >Tiny hulls have very little space but are cheap and only use 2 logistic points. This means you can build bigger fleets of them.< /Description >
< Cost >35< /Cost >
< SensorRange >2< /SensorRange >
< Size >16< /Size >
< HP >6< /HP >
< Model >Tiny_0< /Model >
< Thumbnail >Tiny_0< /Thumbnail >
< Speed >1< /Speed >
< Category >Tiny< /Category >
< Logistics >2< /Logistics >
< Tech_Requirement >XenoIndustrialTheory< /Tech_Requirement >
< /Hull >
So the various hulls can have better/worse hitpoints, size, cost, speed bonus, logistics cost, and built-in Sensor Range.
Could have some fun designing a spread of hulls with that...Like maybe a size-10 sensor drone hull that becomes available when sensors are researched, which has three times the SensorRange.
Or specialized WarpCorvette hulls, that become available with warp drive, that give extra bonus movement point, but are sleightly smaller than a medium hull.
Or weapons platform hull, with a 0 Speed bonus, but a low logistics value.