All great suggestions!
May I suggest
a) keeping the classic trumble mission as classic as possible, and
b) Have various other instances you can get infected with trumbles/ trimbles/ trombles/ grumbles /etc.
For instance:
-scooping an infected cargo cannister.,
-buying a suspiciously cheap ship (it belonged to an elderly trader-lady, honest! trust me.) (hehe, makes me think of cat-lady-syndrome in the future)
-visiting an infected hermitrock (ghost-rock, no comms, just a repeating distresscall. when you dock you find no-one. attacking the rock results in no responce. tradegoods: you find crates full of furs and debris. No-one is around to care, so you figure the price is right (0.00 Cr/tonne!) When next docking in a populated dock, you find that the furs are now trimbles.)
Generating various species of trumble:
have all those suggested properties for them randomly selected upon infection.
Use descriptions.plist to generate strange names for them.
About the cargo warning message...I don't think so, why be able to see trimbles and not the amount of gold etc?
How about an intrusion alert? A modern ship should have motion detectors in the cargohold.
<EXCUSE ME COMMANDER? MOTION DETECTED IN THE CARGOBAY>
OR
<WE SEEM TO HAVE A STOW-AWAY CAPTAIN: LIFEFORM DETECTED IN CARGOBAY>
How are trimbles currently shown? I asume they are (like valuable cargo) converted from tonnes into numbers when player docks?
Come to that: have a chance of trimbles escaping for every tonne of cargo traded. chance of detection varies between govt's/techlevel.
Smuggling noxious lifeforms (pests) is a minor offence, fineable with 500Creds.
A player should only know about trimble snaking when he tries to sell his wines and the buyer gets upset about the noise coming out of the container.
How about a more dynamic trimble growth than doubling at every jump?
Why not use a true time growth rate? and rate modified by several factors such as food available, radiation level, docked or not.