smm doesn't replace the minimap - that is the real minimap. If the Spellcraft button frame is anchored to the minimap, it's going to go wherever the minimap goes. Actually, it looks like there was some miscommunication between you and the Spellcraft author. From reading that, it seems that the author believes the minimap button was left in the original position instead of moving with the minimap. Your problem is with the menu going off screen. Which is an issue with Spellcraft, as I mentioned before.
Because of the nature of Spellcraft, it needs to create its own secure frame to cast spells from, which hides/shows when you click the minimap button. Much like the old Fizzwidget TrackMenu. Gazmik had to put in options to change the anchor/direction of his menu frame so that it would not go off-screen when the minimap was moved to the bottom of the screen. The author of Spellcraft needs to do either the same thing or clamp the frame to screen so that it will auto-adjust and stay visible.
Go back to the Spellcraft author and make sure that they know what your problem is - because I think there was some confusion. Show them your screenshot (again, if you did already). Tell them to take a look at the TrackMenu code if needed (it won't work in-game post 2.3). smm is doing what it needs to do. The issue is with Spellcraft's frame. I'm not much of a coder, but I can see that. :)
Well, smm can move other frames too, like: QuestWatchFrame, CaptureMover, and even DurabilityFrame.
So, to the author, maybe its a feature you'd like to add :)
Those frames are all part of the MinimapCluster - they're anchored to the minimap in the default UI, so smm offers the ability to move them so that they're not lost off the screen when you move your minimap to the bottom. So actually, they do have something to do with the minimap.
Try FluidFrames or Visor2 to see if you can move that text frame.
@Dragane: I'm not much of a coder by any means, but I fail to see how that's an issue with smm. If it is, then I'm just not smart enough to get it, I guess. :) Couldn't the Spellcraft author add in clamp to screen?