Though I'm not so sure about a European online server, I'd love to see some Europe-based single player mods using the Fonline engine, primarily because the single player game allows a level of depth and storytelling which is difficult to get in an online version (because in the single player game, the author has control of every character other than the player).
I just think it would be interesting to see games set in areas currently left completely "open" by the Fallout Bible - bombs went off, places were destroyed - then what happened? - though as many people have said, really needs some graphic work and lots of detailed atmosphere work to "feel" like somewhere else.
For example, for something set in the UK, you'd need to change the buildings, roads, furniture, "street furniture" (signs, post boxes, street lights etc), ground tiles, cliffs, deserts etc... and unless the UK government remained close to the US instead of the European Commonwealth, then you can get rid of all the power armour, and probably all the combat armours too. Radscorpions, geckos and some of the other critters would probably want to go - and what would you replace them with? Giant moths, Rad-hedgehogs, giant rabbits and evil sheep, perhaps? If there was no FEV there, then no mutants, and probably no ghouls, and given the general lack of guns in the country, you'd probably want to get rid of BG, EW and most of the other guns, other than the odd shotgun or pistol. Melee and home-made crossbows, perhaps?
Similar thinking for any other location, like if it was set in France, every character would need to wear a beret, drink wine and smoke gitanes
That's a lot of work, and a lot of planning and thinking, but if it was done well, it'd be awesome.
Otherwise, I think it's good to support any attempt at modding the game, even if you don't like the specific end product, or if it never gets finished - there's a lot of work, ideas and learning which can only benefit the community as a whole - so I wish these guys the best of luck.