I was recently (this morning actually!) fielding a question on Apple’s Discussions boards regarding copying from Excel to Keynote. I could recreate the issue and, simply put, you can’t copy Excel to Keynote and keep it editable. The bigger problem, though, was why was nothing being pasted at all?
Then, I started thinking. What, exactly, is Excel placing on the PasteBoard (The PasteBoard is that universal area from whence all copy and pasting comes from and goes)? Every app I know of at least places a PDF on the PasteBoard and Keynote should have no problem bringing that over. To check, I opened Preview, gave it a Command-N, and there was the PDF file as expected!
From prior problems with Keynote and copy/pasting, I have a copy of clipPDFservant on my Mac. I figured that if the PDF data is there, perhaps it’s suffering from the same iWork limitation that affects PDF’s cropped by Preview. Sure enough, after running clipPDFservant, I was able to paste the image data into Keynote, Numbers, and Pages. Again, it’s not as nice as being able to paste the actual cells and data, but for presentation purposes, it should do just fine.
You can find more info about clipPDFservant and the instructions for it’s installation and use on this page.