There are many different solutions to the T5 in a XR situation.
1 piece (these may vibrate more than 2 piece)
2 piece (more expensive than 1 piece shaft)
A company named Coleman in MI at 906-863-7883 sells driveshafts; aluminum or steel in 1/2" increments from 35-60 inches. Aluminum ($230.00 ), Steel ($170.00) Besure to specify u-joint size!
The front weld-on yoke to convert a Merkur shaft to a T-5 is
SP 2-28-417 (spicer) $18.92
The front u-joint is SP 5-625X (spicer) $16.02
Weld front section 16" center to center of u-joints.
You will also need a front slip yoke from a T-5 vehicle.
I was told by the drive shaft shop they can also convert the other u-joints to the replaceable type.