Its something I was thinking of doing, but never got around to it, but it has 2 parts, firstly:
/twcut - Similar to /twcopy, except it is stored separately and would move the entire region exactly, the issue with /twcopy is that some blocks are not permitted to be pasted. The cut would allow the moving of blocks from one point to another without putting them in/out of inventory, and can only pasted once, something along the lines of /twpaste -cut.
Second, the ability to copy/paste entities, if you do /twcopy, then it would try to paste entities in the same locations, IF you had them stored in your fishing rod moving thingy (or had spawn eggs, for some reason). And if you used /twcut, then it would also take them from your target location and move them. This is not only useful for animal farms, but also buildings with item frames. It could place item frames, and if possible (has items in inventory), it would put the items in the frames.
Bugs to be fixed (if not already)
As a little extra thing for Alpha to have fun with, an almost bug, the /twcopy can be rotated via /twclipboard, but when rotated at unusual degrees, it can sometimes distort, causing 2 blocks to try and share the same pasted location. If this does occur, not only will some blocks not have correct locations, leaving holes in a structure, but the two blocks that are pasted over the top of each other will both paste, meaning that it will paste one block, then next place a block over the top, pointless calculation, and moving items in/out of inventory. This can be fixed with some code, but I never got around to it. It would be a pain to fix, but it can be done.
The next little bug thing is that rotating your clipboard will update the clipboards rotation live, meaning that if you rotate it 80 degrees, it will calculate the new location, then if you do it another 10, it will calculate it again. If you keep rotating it by non-right angled numbers, it will eventually distort. This can be fixed by storing the rotation of your clipboard, and adding to it each time you call -rotate, then calculate it, (but not store it), when you paste it.
Edit: I'm mainly doing this because I want to give Alpha more work to do >: )
