Here's a solution I found. (It's not pretty)
I'm running Leopard, but give this a try. I think that it's a problem with the manufacturer not including an icon in their driver and not Tiger's fault.
Hi, I was recently trying to do the same thing and I came across this post. After spending some time looking online for a solution, I came up with my own. It took about an hour of messing around with things but I finally found a way. It's not for novice users and it's not a complete solution. Here's a step by step of what I did:
1. Create your .icns icon file. I use a free app called img2icns.
2. Download your printer driver (do this even if you already have it)
3. Install the printer driver. (You can skip this step if you've already done it)
4. For my Xerox printer, the driver came as a package file. I don't know about other manufacturers. Anyway, you need to secondary click the pkg and go to "Show Package Contents"
5. Here's where it gets a little tough: You need to find the PPD file for your printer. This varies greatly between manufacturers but with a little searching, you should be able to find it. Remember to "Show Package Contents" whenever you come across any .pkg files. You may have to unzip some things too.
6. Now you have the PPD file. Make a copy of it on your desktop. (⌘C, ⌘V)
7. Place your .icns file somewhere where it won't get deleted. You may want to create a folder for this as you'll also be putting in the driver itself. Know the path of where you put this icon.
8. Now you'll need to edit the PPD file that is on your desktop. Open it with TextEdit.
9. Right below: *APDialogExtension: "/Library/Printers/Xerox/PDEs/XeroxTroubleshooting.plugin", put this string of text on a new line:
*APPrinterIconPath: "/Library/Printers/Xerox/icons/8560MFP.icns"
NOTE: Replace what is inside the quotes with the path of your icon. You do need to keep the quotes around your path though.
10. Save the file (⌘S) and quit TextEdit (⌘Q).
11. Now you should move the PPD file into the same folder as your icon.
12. Open System Preferences and begin to add a new printer.
13. Before you do add the printer, instead of having the driver auto select or selecting from a list, select "Other..." and choose the driver that you edited.
14. Continue adding the printer. Once you have added to the list, you may still see the generic white printer in the System Preferences Panel. This is why this isn't a great solution, but your printer icon should still show up correctly (with the one you made) when you open the Queue and when the queue is in your dock. To test this, click "Open Print Queue..."
I hope this solution solves your problem!
I am running

OS X 10.5.6 "Leopard"