[kevpatts]

I'm putting this up because I've just successfully done this and it was an unholy pain in the arse!

Okay, first of all some notes:

1. THIS WILL ERASE EVERYTHING ON THE WHOLE DRIVE, so backup stuff if you need to.
   
2. Don't use GPT partition table: It simply won't work. Yes you can install windows onto a GPT disk using the Shift-F10 method, but this will leave you with out of sync GPT and MBR partition tables on the drive and they can't be sync'd. Ubuntu (XBMCbuntu) will only look at the GPT table, which won't have the Windows drives listed, and so will erase the windows partition. Nothing I found with gptsync or gdisk could fix this.
   
3. You will not be able to have a single partition that spans more that 2Tb: Because you have to use MBR partition table the drives cannot be larger than 2Tb.
   
4. Install Windows first: To avoid issues with the boot loader, etc. I'd recommend installing Windows first.
   
5. Do not delete the Windows reserved system partition: This is required for Windows to boot.
   

Restrictions that make this a headache:

• Max of 4 Primary partitions (or 3 Primary and one Extended).
  
• Logical partitions can only be inside Extended partitions.
  
• All Primary, Logical and Extended partitions must begin in the first 2Tb of the drive and cannot be bigger than 2Tb.
  
• Windows cannot boot from an Extended partition, it requires 2 Primary partitions.
  
• Ubuntu is recommended to have 2 partitions (swap and "/" (root)), however these can be Logical partitions within the Extended partition.
  
• Because of above I recommend having both Windows partitions and the entire extended partition (containing the XBMCbuntu partitions and maybe another partition) within the first 2Tb (a little less in fact) or the drive. The last primary partition can then start within the first 2Tb of the drive and fill the rest.
  

What you'll need:

• Windows 7 installation disk
  
• Ubuntu 11.10 or higher (desktop) LiveCD
  
• XBMCbuntu LiveCD
  

Procedure:

1. Write Boot Sector: Boot to the Ubuntu LiveCD and start GParted. Select the relevant hard drive, click "Device" menu and "Create Partition Table..." and set it to "msdos" (MBR). This will erase verything on the whole drive.
   
2. Install Windows: During the installation delete whatever partitions are there by default and set up the Windows partition the size you want it, in my case 50Gb (51200Mb). It will create a 100Mb system partition when you do this. Finish the Windows installation but don't go mad configuring/updating it yet, cause if something goes wrong you may have to re-install.
   
3. Create other partitions: Boot into Ubuntu LiveCD again and start GParted again. Create the other partitions you will need. I've listed my layout below.
   
4. Install XBMCbuntu: Reboot and install XBMCbuntu to the Ext4 root partition.
   

My partition layout looks like:

Code:

sda1: 100Mb PRIMARY NTFS Windows System (boot) partition
sda2: 50Gb PRIMARY NTFS Windows partition
sda3: 1.91Tb EXTENDED partition
    sda5: 4Gb LOGICAL Linux swap partition
    sda6: 50Gb LOGICAL Linux Ext4 root partition
    sda7: 1.9Tb LOGICAL NTFS partition (for Movies in my case)
sda4: 1.64Gb PRIMARY NTFS partition (for other media in my case)

You should now have a Dual boot with full drive usage.

Best of luck.