How do I copy an NTFS partition to a writable disk image? I have a drive from an old Windows computer. The drive is now in an enclosure, so it's accessible as if it were an external drive. It is formatted as NTFS. I would like to convert this drive (about 50 GB, including Windows XP on it) to a writable disk image.

I tried using Disk Utility to convert it to a read/write disk image, but it doesn't work because it still results in a disk image with NTFS as the format, which Mac cannot write to natively.

So, how can I convert the NTFS disk image that I now have (or the original drive) to a writable disk image? This will probably require that it be converted from NTFS to FAT32 or HFS+ somehow. I could just take the basic approach and copy the files themselves, but is there a cleaner way by copying it as an image?
Alright, so after browsing around, I figured that I could just Carbon Copy Cloner to copy the NTFS's contents to a proper sparse bundle or sparse image. That's probably the best way to go!