Can you change the way Ubuntu 12.04 looks so that the menu systems look like those from 11.10?
Does it not already? Ubuntu 11.10 had Unity by default, and the applications lens of the dash hasn't really changed. The only big difference I can see is that 12.04 no longer has the "home" screen of the dash. It just defaults to recent search results, I think.
12.04 already looks like 11.10.
With regards to your menu system looks, maybe you were using a different GTK theme.
Why not explore some of the other themes that ship with 12.04. You can change themes using My Unity available in the Ubuntu Software.
Also please review this question How Do I Configure Unity? as it will give you option to change the look and feel of your desktop to suit your tastes