Speed parameter for 'dd' command

[sdrb]

Hello,

I'd like to ask if it would be possible to add new parameter to "dd" 
command. I was thinking about "speed" parameter. Sometimes it is needed 
to use "dd" with very large amount of data and the whole process can 
cause quite high load average for long time.
Maybe it would be good idea to add some kind of limitation for "dd" 
command - and limits I/O operations to given kB or MB per seconds?
For example:

        dd if=/dev/zero of=/dev/sda speed=4096k

and it will limits I/O operations to 4MB/s?

Of course the whole "dd" process will take more time to complete in this 
case, but at the same time it will be possible to keep load average in 
more acceptable values and thus make using system more comfortable.

What do you think?