Yes, Its possible to provide MOSS 2007 User interface to the SharePoint 2010. There are two ways:
- If you have upgraded from MOSS 2007 to SharePoint 2010 using an In-Place upgrade, then you will be able to do it by GUI. Here is where: Site Actions >> Site Settings >> site collection administration >> Visual Upgrade
- You can do the same with PowerShell. Of course, if you have a new installation or DB attach method used, you can do this ONLY with PowerShell.
So here is the result, With UIVersion 3:
With UIVersion 4: