The Scandinavian mountains reach from Stavanger in the south to the North Cape in the north. You can easily explore where mountainous areas are via the interactive topographic maps of Norway and Sweden. Southern Norway is geographically closest, but is less well connected, with only few trains connecting Malmö with Oslo. You might find that it's just as fast to take the train to Östersund (central Sweden), from where you can quickly reach the central Swedish mountains. It probably depends where in Germany you are: from northern Germany you may be able to reach Oslo in a day in time to take the sleeper train north or west into the mountains, from southern Germany you'd need at least an extra day (or an overnight bus, which sucks).
I've been to southern, central, and northern Norway, as well as to central and northern Sweden and northern Finland. Broadly speaking, the mountains look roughly similar, but with significant differences, so whether the other mountains are "like that of Abisko" is subjective. I know some valleys that somewhat remind me of the Abisko valley, but they all take longer, not shorter, to reach (and get at least two orders of magnitude less hikers).
In practice, I think that if you're traveling overland to the Scandinavian mountains anyway, then the extra time it takes to travel to northern Sweden is not that huge, considering there are two trains per night going there from Stockholm.