First of all, thanks for the info DaveS, bm0p700f and ChrisW, much appreciated!
I think that I will get myself a bike with the Athena compact and the 'double' shifters and will do some measurements to see what I'll need to buy to make the Campa triple happen. Perhaps the option of ChrisW with the lightning crankset could be a nice light alternative - although they do not come cheap and I'll have to check how I can get this crankset in/to the UK. Positive would be that I can most likely keep my shifters and derailleurs.
If anyone knows of other alternatives to modify a new Athena Compact equipped bike to have a lowest gear of something around 30x29 and still have a 'decent' top gear (e.g. 45x11) - preferably of course without breaking the bank but also not the scale...
With regards to the compact/triple discussion... I basically would love to be able to use a really low gear like 30 x 29 when I'll be climbing the Mortirolo (profile
), the Gavia and the Stelvio. It'll be nice to be able to spin instead of grind my way up. And having the 11 cogs in the back will be nice to find a good rhythm. But everyone his/her own of course!