The belt drives:
alternator - can do without
compressor - can do without
water pump - can do without if you drive 1 mile and rest for 1 hour
power steering - you may have a hard time steering it. I find it very hard to steer without power steering on a 300D.

In theory, it is possible. In practice, you need to rest and let the engine cools down.

Have you ever thought of using penty hose to wrap round the water pump?

http://photo.net/photodb/photo?photo_id=8396293

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.