I was actually playing around with separating the UV shells in the Hard Edge version earlier today, and yes it more or less completely eliminated the nasty edges. Now it hit me that there is a "Warp Image" feature in Maya that lets you transfer texture data from one UV set to another UV set. So I figured maybe I could bake…
Yeh, if it was a closed mesh with bottom corners then you'd definitely need more supporting polys, or split normals. The other solution too, which a lot of people overlook I think, is to manually edit your normals. A little tweaking here and there can produce a perfectly nice normal bake with no extra overhead. No time…