Now, my one is only three parts, but it should be interesting enough.
I suggest to use the DBSetXL as it contains Swiss town names, so that should about fit.
Unfortunately, Alpine can not be used, as it is a temp map, rather then arctic...

Further more, you will not be able to avoid building certain mountainious lines, as you will see from attached map.
And, to add to the challenge, there is no industries placed on the map, so you will have to see what the game serves you up as you go along. On the other hand, that should allow you to concentrate on building up a nice passenger network, until some industries appear.
EDIT: Another thing I inteded on this map is to have the possibility to make a nice mainline as well as having the possibility for nice branchlines into small villages and along some coastlines.
Make sure that you trim the filename back to the standard format for TTDPatch savegames. So it should be something like TRPXX.sv0, where as XX stands for any no between 00 and 99 which does not yet exist in your TTD directory.
I would be happy to see some screenies.
Now, good luck with the challenge.