There is no software on any platform that I'm aware of that will backup a multiple boot system to another drive and allow you to simply swap drives as if nothing happened.
What has worked for me and has been pretty painless - as in less than 2 hours to be back exactly where I left off with a new drive - I have a dual boot system with Win 7 Ultimate on the BootCamp partition along with XP installed in VMWare.
An external drive - created 3 partitions on mine - one for OS X, one for Windows and one for other data. You would need to consider what you require. this particular external drive of mine include both, 10.5 and a 10.6 bootable clones along with the Winclone partition.
I use SuperDuper! to create a bootable backup.
After re-booting to the OS X backup and making sure it works... boot back to your internal drive.
I then use Winclone to backup the Win 7 partition - make sure the partition you backup Windows to on the external is formatted as NTFS.
(Note: There are some experiencing difficulties with Winclone not restoring. I have not experienced this and have done 3 restores to a new drive in my MBP this year - at that time I believe from 10.6.5.)
(Note: I also use Paragon's NTFS for Mac - don't really know if this is what has enabled mine to work when others haven't).
To restore is exactly the opposite:
Install the new drive
Boot to my OS X backup
Use Disk Utility to partition and format the internal.
Use SuperDuper! to backup the external to the internal.
Boot to the internal and verify it is working.
Open up BootCamp Assistant and create the partition for Windows, then exit out of BCA.
Boot to the OS X external.
Open up Disk Utility and format the BootCamp partition on the internal to NTFS.
Then use Winclone to restore to that partition.
The whole process from the time I begin taking apart the MBP, moving almost 250GB of data (via FW800) onto the new drive, is well under 2 hours. Not bad for restoring a dual boot system.
Winclone is still available on several 3rd party software sites including cnet's
download.com.