Swedish Digg-clone Pusha has acquired Swedish Digg-clone Färskpressad. Neither have gained real traction, but hopefully merging can push them closer to critical mass. The next logical step for the combined entity is to merge with Hypa. I don't see room for more than, maximum, one successful Swedish Digg-clone, and creating one I think is really tough. As long as there are several clones, they are likely to hurt each other as everyone have a really hard time reaching critical mass.
If you want to build a service in Swedish, I don't think you should build a niche geek service when there is a really strong competitor in English if it isn't a labor of love.