I don't know why you say it's difficult to connect two 1.1mm traces. Here is an example of a split block fixture:
**broken link removed**
For THRU calibration you just remove the transistor, bolt the two fixture halves together, and bridge the traces with a piece of leadframe. Same for the LINE standard, just drop it in, tighten the fixture, and bridge with leadframe.
The SHORT is a little tricky since you cant solder from the end of the trace to the metal block, but you can pack Indium foil at the end of the trace to short against the block.
quangt,
That methods works well for tuning assuming you don't want to do a true, automated load pull analysis. However to look back into the fixture with the VNA still requires a well established reference plane, which you get when you do a TRL calibration. I agree that the connections do not have to be the width of the transistor leadframe (I have done pre-matching fixtures with 12 ohm LINE standards) however when mixing and matching steps at the reference planes you had better be very careful to account for the discontinuities or else you will blow all your measurements.