It's always struck me as a bit of a shame that trainers are only considered "interesting" once they're painted with cammo and hung with ordnance, so how about:
The Teacher's Pet Ride GB (aka Trainers-Are-For-Training)
Build a whiff aircraft, ground vehicle or ship whose purpose and current role is training and whose colour scheme and equipment reflect this. Any armament should be for target practice purposes ONLY, not for actual live combat.
Some ideas:
1. Real aircraft, real air force that really uses it, but alternative colour scheme. Examples:
USAF T-38 in RAF-style gloss black
RAF Hawk in orange and green
2. Real aircraft in service with a real air force who don't really use it. Examples:
Armee de l'Air T-38
Brazilian Gnat
Canadian Jet Provost
USAF Tucano
3. Real aircraft in service with a fictional air force. Examples:
L-39 Albatross in Backofbeyondistan colours
Yak-18 in People's Republic of Greater Manchester colours
4. Fictional trainer version of real aircraft. Examples:
Tandem-seat Hunter T.7
Side-by-side Mirage IIIB
2-seat Skyray
Sea Vixen trainer with Vampire T.11 canopy
5. Completely fictional aircraft.
6. Training version of ground vehicle. Examples:
Driver training version of any tank or tracked vehicle that didn't actually have one. Turret replaced by glass box for instructor, fitted with ballast weights and fake gun barrel.
M1 Abrams tank on a firing range in 2050: painted bright orange with laser-holes in the side.
7. Fictional cadet or pilot training conversion of an existing ship. Examples:
Arleigh Burke class destroyer with all weapons except the 5" removed and extra accomodation blocks instead of the VLS and hangar.
Any container ship converted to a helicopter training ship along the lines of the RFA Argus.