Hi bhkyte,
Well as far as cost is concerned, the Mezzo conversion was not cheap.
The Alfine 11-speed hub was about £450 with rebuildiing of the wheel (had to get a Sun 32 hole wheel for this-the wheel cost about £30), and the shifter was about £64. So a lot of cash, but I justified this to myself on the basis that I don't plan to change this for several years. I can't imagine why I would change it anyway, as far as I am concerned this is the perfect folder for touring using public transportation. The only way it could possibly be improved for me would be if it were lighter, but I don't see that as being likely unless there is a miracle alloy on some distant planet that we don't know about yet.
One other modification is that I am replacing the small rather inefficient wheels on the carrier which don't work very well when pushing the bike folded over uneven concrete with a pair of Brompton eazy wheels.
I have enjoyed the convenience of putting the mudguard strut in the Sockal clip to secure the fold. So I think I will persevere with that. Thanks for the suggestions about the Sockal clip issue. Inspired by you and "bostonblackie" I am going to try to relocate the Sockal clip using a mending plate.
I'll put some photos up once I figure out how to work the camera.
One last point about Brompton versus Mezzo. As I mentioned before, I also have a Brompton S6R-X9 (sport bars, 6 speed, rack and mudguards and titanium bits). There is no doubt that nothing beats the Brompton for compactness when folded (slightly smaller than the Mezzo), lightness and versatility. If I had to have only one bike I might go with the Brompton, especially for short commuting. However, when it comes to touring with intermittent public transportation I find the Mezzo, particularly my current version, much more enjoyable, and as people keep saying to me in France, tres practique.