Yes, but a Live CD is also slower than native.

If you want to try out Linux just use Wubi and you have Ubuntu installed (and easily uninstalled) in no time on the Windows NTFS partition in c:\ubuntu. Reboot, and boom you're on Linux. All ~native speed (maybe some overhead from NTFS :P). You can even access this installation via VirtualBox.

If you want to try or run KDE on Windows see windows.kde.org.

If you want to do maemo porting/development try my method above. VMware Player instead of VirtualBox would also work. Or consider a method like coLinux/andLinux.

BTW, newer CPUs with AMD-V or Intel VT are able to run VMs at almost native speed (90-100% sometimes even more than 100%). Provided your VM supports these hardware extensions there is almost no overhead then.