YES! It works. Please ignore most of the previous answers.
I have done it using a 10.4.10 install DVD. On first boot, the backlight didn't work, so I had to do all the registration stuff in the dark trying to make out the text as best I could. Also the trackpad wasn't working (or at least, I couldn't see the cursor cos the screen was so dark!)
Go straight to Software Update and download and install all updates, including 10.4.11. After doing this and rebooting, the mouse woke up and the screen started working perfectly.
The only differences between the old 2.2/2.4 MBPs and the new ones is the multitouch trackpad - all other hardware is the same so drivers aren't an issue.
I haven't checked the iSight, can't remember how many of the trackpad's extra features work (scrolling etc..) and I don't remember if the backlight auto-adjusts like it's supposed to - but it works. I've been using Tiger with Pro Tools M-Powered and the rest of the OS is perfectly happy.
Just be sure to start with a RECENT (ie. 10.4.10 as I did) install DVD and update to 10.4.10 as soon as you're done.
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To make the 10.4 DVD allow installation, you need to edit the OSInstall.dist file inside the OSInstall.mpkg file found in System\Installation. Towards the bottom is a list of allowed machines ('GoodHardware' if I remember rightly?). Depending on what disc you use it might be large or restricted to a single model only. For the new MBP you need to add MacBookPro4,1 to the list. Save and reboot using the DVD.
If the DVD doesn't play ball, you can still install Tiger onto your Tiger partition from inside Leopard. Go back to the DVD and manually run the OSInstall.mpkg from earlier. Follow the install making sure to install it on its own partition. Give it a while to copy the files and hey-presto, a fresh OSX install from within Leopard!
That's a very condensed tutorial - there are fuller, better ones out there if you need a bit more guidance. Have a search for installing OSX on different hardware and you'll find the important bits - the principle is the same as what you need to do here, even if there are no specific MBP4,1/Tiger tutorials written yet.
Enjoy!
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edit: A bit of background - yes I'm a new poster but have been lurking for a looong time and am not new to this sort of thing. I'm posting from my Triple-Boot Leopard/XP/Tiger(+DATA partition) MBP4,1. Even that sort of partitioning was generally thought impossible cos of MBR
