So I'm just playing around here.
Here's a race based loosely on the Snathi (pic, ships, etc)
They have All Bonuses, except Synthetic.
They start with 4 colony ships, 3 scout ships, and 3 survey ships.
They start with 10,000 credits, and I tweaked their influence default.
They start with 5 planets in their Home System - they are all Class 16 and have some sort of beneficial Planet Effect.
Yes, they are extremely overpowered. Let the AI run them if you want a challenge. 
http://s000.tinyupload.com/index.php?file_id=58080358397139057380
Files Modified:
None
Files Added:
FactonDefs_Rats.xml
PlanetDefs_Rats.xml
StarSystemDefs_Rats.xml
FactionText_Rats.xml
StarSystemText_Rats.xml
Limits / Things I want to fix:
The starter planets - I tried setting their default name, but they all get the Homeworld name as their base.
No way to remove Snathi as a race without completely replacing FactionDefs.xml - if they give us a remove option I can fix that.
I couldn't figure out an easy way to give them 3 constructor ships to start with.