Other than manipulating the various mapgen parameters, hoping for something similar to your desired output, the only real answer is a Lua mapgen.
Carpathian and Valleys both exist as a lua mapgen, but are much slower. If you search for the grunds mod, it contains code that will, with modifications, allow you to generate mg_v7 terrain, without ridges, mountains, caves, or floatlands.
I've worked towards making "continental" sized landmasses, with realistic mountains, true oceans, and other assorted geologic wonders. I've been using voronoi cells and a basic 2D noise to accomplish most of this. A 3D noise for generating a 2D heightmap, while preserving the 3D overhangs, to make more appealing terrain, but again, lua mapgens are slower. If you're willing to be patient, however, they are far more rich in what can be accomplished.
Shad