Odd, the B110 and B210 use the same tailshaft, even though the B210 wheelbase is four centimeters longer ... is this because the B210 transmission is 4 cm longer?

Wheelbase
B110 2300 mm
B210 2340 mm
B310 2340 mm

For the B110, they changed design several times, but apparently all are the same length as they interchange. Coupe, Sedan, Wagon all use the same tailshaft. But autos and manuals use different ones.

tailshaft (driveshaft) JAPAN models

B110
Note: Solid type has replaceable u-joints held in with c-clips
Manual
37000-H1001 SHAFT COMP-propeller with joint (Solid type)
37000-H1010 SHAFT COMP-propeller with joint (Solid type) from '72-6
37000-H1011 SHAFT COMP-propeller with joint (Solid type) from '72-9
37000-H3100 SHAFT COMP-propeller with joint (Shell bearing type)
...from '72-8 chassis numbers B110-693162-693170, B110-745001-774572
...from '72-10 KB110-981350-999999, KB110-550001-554409
Auto
37000-H1101 SHAFT COMP-propeller with joint (Solid type)
37000-H1110 SHAFT COMP-propeller with joint (Solid type) from '72-6
37000-H3200 SHAFT COMP-propeller with joint (Shell bearing type)
...from '73-3 chassis numbers B110-767755-774572
...from '72-10 KB110-981519-999999, KB110-550001-552609
37000-H5100 SHAFT COMP-propeller with joint (Shell bearing type) from '73-2

B210 (5-speed and twin-carb models had 3-joint shafts i.e. two-piece shafts)
37000-H3100 SHAFT ASS'Y-propeller (2-joint)
37000-H7200 SHAFT ASS'Y-propeller (2-joint) from '74-9
37000-H5100 SHAFT ASS'Y-propeller (2-joint) AUTO
37000-H7300 SHAFT ASS'Y-propeller (2-joint) AUTO from '74-9

B310 (EGI models used 3-joint shafts)
37000-H8500 SHAFT ASS'Y-propeller (2-joint)
37000-H8900 SHAFT ASS'Y-propeller (2-joint) AUTO

B120/B122 Shortbed 1976-up (longbeds use 3-joint shafts)
37000-G1011 SHAFT ASSY-PROPELLER (2-joint)

Thanks for the info dd.
I am starting to understand some of the differences.

I was confused because I run a H165 centre and use a ute tailshaft with a 40mm alloy spacer in my coupe(makes perfect sense with reference to your post). I was previously told that a coupe or sedan tailshafts would not fit. I assumed he was refering to the length but now I understand he must have been refering to the rear yoke where it bolts to the diff pinion flange.

Cheers.

I had to have the tailshaft on my ute shortened after I bought it. It had a recent A12 put in it by the previous owner and then he sold it. The mechanic that did the swap must not have realised this - or just been dodgy. The ute still has the 1000 4sp in it so I'm thinking that the engine may be the differing length as opposed to the transmission. Although I was new to Datos then I'm a bit disappointed as I reckon I could've just gone to a wreckers and bought a 1200 tail shaft instead of shelling out $$ for the shortening of the 1000 shaft.
but it's done now and you know what they say about spilt milk.

I measured the tailshaft in my garage -- the one I used behind the 60a 5-speed. It is the same length as the one in my 1200 (stock).

Here are the measurements:

overall length, diff flange face to end of yoke: 132.5 cm
shaft length u-joint center to center: 11880 mm (118.8 cm)
slip-yoke length u-joint center to end: 106 mm
slip yoke sliding length: 68 mm
slip-yoke diameter: 30 mm
diff flange lenght u-join center to flange face: 31 mm
diff flange mounting bolt holes center to center: 50 mm x 45 mm
Diameter of flange circle that fits into H145 diff: 38 mm

.<-50 mm->
|---------|
|O /.-.\ O| |
| (-38--) | 45 mm
|O \._./ O| |
|---------|

Surprisingly this is not square.

u-joint cross dimension: 56 x 56 mm
u-joint bearing O.D: ~19 mm