You are a lucky man to leave close to BAd Dad....I'm only 5,000 km away but internet is everything. It wouldn't be possible to exchange so many info without it. I spoke with Adam at Bad Dad back in October when I was researching the hole project and I understood that they can do decent job, but I felt that If I wanted to go all the way custom I had to find a custom builder with experience. You see there isn't much room for error since the bike will end up in Greece. Warranty issues are a main concern as is reliability and durability...
One of the guys I felt very comfortable with is Paul Yaffe (http://www.baggernation.com).Check it out. He has a degree in Engineering and his bikes are always in the media, plus he makes a lot of parts for Baggers.
Paul does some top notch work I've seen it in person at trade shows! You will pay for it but should get what you expect.
Bad Dad is not going to be the quality level of Yaffe's shop they dint have his budget. The exterior finish is good but the undersides are less finished.
FBI is mostly bolt on modifications so it shouldn't affect reliability and they also have high quality seen their work at Sturgis.
Arlen Ness also uses top quality and can complete the build to your specifications. Arlen is easy to talk to and work with.
I've only seen the Milwaukee Bagger info on the website bu it looks like they deliver a quality product as well.
If you asked me to pick it would likely come down to Arlen Ness or Paul Yaffe especially at that distance.
I would also come to inspect the bike here before taking delivery, Just to be confident it was right and watch it get loaded in the container properly.