Hi DaveR,
Follow this steps:
1. Goto InsertWordArt.
2. Select the very first WordArt.
3. Edit text type DRAFT make size bigger "96"
4. Select the text left click goto Format WordArt.
5. Choose Fill color light gray click semitransparent.
6. Choose Line color - no line.
7. Select text again left click goto order send it at the back.
I think this might do unless you got a photoshop and do a gif file
with transparent background and paste it to powerpoint.
Hope this helps.
7.