more than 2 partitions with bootcamp

There certainly can be side effects but not if you use the right tools. Above all, do NOT use a Windows partition manager for this task. All the ones I've tried so far have caused big problems due to the fact that Apple's implementation of GPT (the partitioning scheme that's probably used by your MacBook Pro) is slightly customised and not the standard GPT scheme.

You'll need to use a product called iPartition, from Coriolis:-

http://www.coriolis-systems.com/iPartition.php

It has its drawbacks:- the demo version doesn't allow you to commit any changes IIRC. And also, you can't run it from your Mac's hard drive (it has to be burnt onto a separate boot DVD). And it's not entirely great at formatting Windows partitions. But apart from those issues it works exceptionally well. Bear these points in mind though:-

1) Create your new partition using iPartition, then format it with a Windows utility.
2) Format it for FAT32 (NTFS is read-only when mounted by OS-X, IIRC).
3) It's very unlikely that you'll be able to create more than one extra partition. Although a GPT drive supports up to 128 partitions, almost no currently available partition manager seems to be aware of this, so you'll be restricted to the usual 4 partitions - EFI, HFS (for OS-X), NTFS (for Windows) and FAT32 (for your shared data).

Some partition managers will allow you to create more than 4 partitions but if you create any, you'll only make the drive unreadable by other partition managers..

Some side effects:

volumes aren't available on the other platform
may not be able to change startup disk default OS
could impact disk repair programs for OS X

And yes, non-standard 😟

I have seen people use Vista to shrink the partition and make room (if there is enough) for Windows 7, but 7 would never show up from OS X or startup disk, and you then use Window boot manager.

My solution would be to build a PC or run only one other OS natively and the others in Fusion.

It is possible to have at least one HFS volume and two NTFS (or FAT 32) volumes. I did that on my MB 13' mid 2006 with MacOSX 10.5 Leo and WinXP. But do not use any Windows partition managers. All you need is in Mac OSX. You can make additional volumes by cutting necessary space from your Mac OSX volume, not from BOOTCAMP volume.

1) First create BootCamp partition of necessary size using BootCamp Assistant.

2) Install Windows, BootCamp drivers for Windows and updates. If you have Windows already installed you probably need to rearrange space between Mac OSX and BOOTCAMP volumes, because you can cut necessary space for the new volumes only from your Mac OSX volume, not from BOOTCAMP volume. I think (but not sure) you can do this without loosing any data using BootCamp Assistant, but if not - you can use WinClone for that purpose.

3) Install NTFS-3G and MacFUSE (to have read/write access to the NTSF volumes while boot in Mac OSX). You can google to download NTFS-3G and MacFUSE (they are free).

4) Boot into Mac OSX and create a new partition of necessary size using Disk Utility (let say the name of that volume will be DATA and it will be NTFS partition).

5) Now you'll need to boot from Mac OSX installation DVD (or external drive with Mac OSX installed on it) and either using command line <diskutil eraseVolume NTFS-3G DATA disk0s3> (without brackets) in Terminal or using Disk Utility (if you boot from Mac OSX 10.5 and later) format DATA partition as NTFS-3G volume. Check in NTFS-3G utility that both BOOTCAMP and DATA volumes are in the list of NTFS-3G volumes. Using Text Editor change bootable Windows partition from 3 to 4 in the boot.ini file at BOOTCAMP volume. Check that Windows is bootable and both C:BOOTCAMP and D:DATA volumes are shown in Windows Explorer. Both this volumes are read/write accessible when you boot either from Mac OSX or Windows.

6) I don't exactly know is it possible to make one more extra Mac OS volume (as you whant) and have your Windows still bootable, but you can try.

May be too much words and seems to be very complicated? Sorry, I'm not native english speaker/writer. But actually you can do that (except Windows installation if needed) just in half an hour. Let me know will it work for you or not.

Bobby78 wrote:
6) I don't exactly know is it possible to make one more extra Mac OS volume (as you whant) and have your Windows still bootable, but you can try.

Yes that is possible. I once did it myself when I wanted to try Parallels without screwing up my main OS-X boot partition. I ended up with two bootable OS-X partitions and one Windows partition.

There are side effects when you shrink and add more partitions.

An external drive would avoid all that.

Small but important addition to my previous post: at step 5) you need to unmount DATA partition in Disk Utility before formatting it as NTFS-3G (or FAT 32).