Here are the parts I have modelised. I have modelised many parts with Solidworks and converted them to dat with my converter stl2dat.
I made the shock absorber springs with my spring2dat utility tool.
Some tips I use to modelise the parts.
All dat file mkdat.zip
Technic Panel #20, #21, #22, #23 44350.zip
Technic Brick 4 x 6 with open center 2 x 4 32531.dat studx.dat
Technic Brick 6 x 8 with open center 4 x 6 32532.dat studx.dat
Tyre 28 x 70 32078.mpd
Wheel 28 x 70 32077.mpd
Tyre Technic Racing 32296.mpd
Tyre Technic Power 32298.mpd
Wheel Technic Racing 22969.mpd
Technic Turntable 3 x 5 x 1 (in Droid Developper Kit) 32273.zip
Technic Liftarm 1 x 9 x 2 1/2 (Used as suspension arm in Silver Champion) mk0014.dat
Micro Scout mkms.zip
The two complete assembly for Droid Developper Kit (mk0010.dat)
and Dark Side Developper Kit (mk0011.dat)exist.
32439 Technic Disc 5 x 5 (slizer wheel) 32439.zip
6578 Wheel 30.4 x 14 VR 6578.mpd
4701 Technic Pneumatic Cylinder with 1 Inlet Medium, Cylinder
Technic Pneumatic Cylinder with 1 Inlet Large, Cylinder
Technic Pneumatic Cylinder with 1 Inlet Medium, Piston Rod
Technic Pneumatic Cylinder with 1 Inlet Large, Piston Rod
oldcyl.zip
Technic Pneumatic Compressor Pump
2793 Technic Pneumatic Cylinder with 2 Inlets Medium
Technic Pneumatic Cylinder small
2797 Technic Pneumatic Pump new
4694 Technic Pneumatic Switch
4696 Technic Pneumatic T Piece
pneumatics.zip
Technic Connector 3 x 3 with ball housing 32172.dat
Technic Horn 2536c.dat
Technic Gearbox 4 x 4 x 1&2/3 6585.dat
Tyre 81.6 x 34 ZR 32196.zip
Wheel 81.6 x 34 ZR 32197.zip
Technic Liftarm 3 x 7 x 2 Y shape 32308.dat
Technic Block Connector 5 x 3 x 1 (Cylinder housing) 32333.dat (Modelized with A.E. Kooiker)
Brick remover 6007.dat
Technic Competition Arrow 32133.zip
Technic Liftarm 1x6 w/ decoration (mockup) 32177.dat
Dragon Wing dragon3.dat
This part is still under progress.
Philippe Urbain has modelized the part. It's on ldraw
Official Update 2002-03
2741 Technic Steering Wheel Large 2741.mpd
Technic Brick 4 x 4 with open center 2 x 2 32324.dat
Official Update 2002-02
Technic Connector 2 x 3 with ball housing 133.dat
Technic Gear Rack 1 x 12 with Holes 32132.dat (based on 6630.dat by Remco Braak 1997)
32527 Technic Panel Fairing #5
32528 Technic Panel Fairing #6
32535 Technic Panel Fairing #8
32534 Technic Panel Fairing #7
panel2.zip
Official Update 2001-03
Technic Liftarm 1 x 7 with 2 ball joints 32173.dat
Official Update 2001-01
Technic Rotor 3 Blade with 6 studs 32125.dat
Official Update 2000-01
Minifig D2R2 Body 30361.dat. I made this part together with Marc Schickelé.
Technic Destroyer Droid Feet 32310.dat (Modelized by A.E. Kooiker)
Technic Gear Rack 1 x 14 with Holes 32185.dat (based on 6592.dat by Remco Braak 1997)
Technic Driving Ring Extension 32187.dat
Technic Gear 20 tooth beveled g12d.dat
Technic Gear 12 tooth double beveled g20d.dat
Technic Gear 20 tooth double beveled 32198.dat
Electric 9v Battery Box big 2846.zip (Contains 2846.dat, 2847.dat, 2848.dat, 2846c.dat)
Technic Shock Absorber, Dumped 32181.zip (Contains 32181.dat, 32182.dat, 32183.dat, 32181c01.dat, 32181s01.dat, 32181c01.dat)
Technic Shock Absorber, 9.5L 2909.zip (Contains 2909.dat, 2909b.dat, 2909s01.dat, 2909c01.dat)
Technic Gear box (used in Throwbots, Crane Truck) 32166.dat
Technic Driving Ring 6539.dat
Technic Changeover Plate 6631.dat
Technic Changeover Catch 6641.dat
Technic Throwbot Head 32165.dat
Technic U-Shape Beam w/Axle also known as Throwbot foot mr0079.dat
Technic Large Pulley 3736.dat 3736sp.dat
32188 - 32191 Technic Panel #1 - #4.
32188.dat 1 kb 32189.dat 88 kb 32190.dat 1 kb 32191.dat 88 kb
Technic Tread 32007b1.dat 32007b2.dat 32007b3.dat 32007c.dat
32007 Technic Tread Hub 32007.dat
32137 Technic modular connector 32137.dat
32136 Technic double pin with axle hole 32136.dat
Technic Clutch gear x3648c.dat x3648ce.dat (center) 35 kb + 5 kb
I made the tread and tread hub for Jonathan Knudsen for an article for O'Reilly : Building instruction for Robotag of book The Unofficial Guide to LEGOŽ MINDSTORMS™ Robots