From my experience with belt sanders, it would:
A. Have a tendency to yank the WB right out of your hand (and pitch it across the workshop at high velocity, if it doesn't hit you first)
B. Take material off too quickly
C. Take material off unevenly, b/c of A & B
Then again, I've only worked with two oversized belt sanders (8"x~80" belt...), and one palm sander.
<off-topic>IBDA:
http://www.beltsander-races.com/</off-topic>