I setup my front crank on my RANS Rocket with a half-step and granny setup.
Works pretty smoothly. It has a 54/50/30 setup. Flipping between the 54 and 50 is pretty simple.
I did have to file something. Because the inner plate of the chain cage on a triple front derailler
drops down to much I had to modify a double front derailleur by filing the high stop.
Here is the crank area setup.
1) 118.5 mm Ultegra bottom bracket.
2) Ultegra Cranks.
3) 54/50/30 chain rings.
4) Shimano RSX double front derailleur. (old stock @6.95 from Nashbar.) I had to file down the high
stop considerably so that I could get the derailler to travel over to the outer chaing ring since
I was using 118.5 bottom bracket.
Feels nice. The jump between the 54 and 50 feels slight. It might not feel like much when casually
test it, but I believe that on long tours you will notice. (I remember Miguel Indurain saying he
lost a stage because he could not get a in between a gear.)