Still when it came time for me to do this i realised that i didnt have a bootable partition utility handy (TODO: i need to find out which Linux boot disk utility to use for next time). However i worked out you can force Windows 7 to install on just a single partition using only the basic and very limited parition tool that comes with the Windows 7 installer. I found the method i used amusing - it reminded me of those classic maths puzzles where you have to end up with Y litres of water using only a 3L and 5L jug.
- Boot into OSX - Use Boot Camp Assistant to remove the existing RC Windows 7 partition and its associated 200Mb boot partition, so that there is only the OSX parititon and its 200Mb boot parition remaining.
- Restart Boot Camp Assistant to resize the OSX partition right down (i used the minimum of 25Gb) and assign the rest to Windows
- Restart using the 64-bit RTM boot disk and go to the partition utility (Advanced)
- Delete the Boot Camp partition to leave the OSX boot, OSX main and unallocated space
- Create a new paritition in the unallocated space. Windows 7 will automatically create the 100Mb boot partition.
- Delete the Windows 7 boot partition so there is 100Mb unallocated space
- Create a new partition in the 100Mb unallocated space
- Delete the larger, older Windows 7 main partition
- Extend the 100Mb NTFS partition to whatever size you want your Windows OS & programs partition to be (i used 100Gb)
- Create a new partition in the remaining unallocated space (mine was 172Gb)
This left me with the desired 4 partitions:
- OSX boot - 200Mb
- OSX main - 25.9Gb
- Windows main - 100.1Gb
- Data - 171.9Gb