I found very useful CAL program.
Free Gift for MIDI Programmers
It randomizes velocity. Here are the instructions:
Copy and paste the following into Notepad. (start with semicolon ).
_____________________________________________

;

(do
(int max 127)
(getInt max "Enter max. velocity value:" 0 127)
(int min 0)
(getInt min "Enter min. velocity value:" 0 127)
(int ofs (random max min))

(forEachEvent
(do
(= ofs (random max min))

(if (== Event.Kind NOTE) ; Is it a NOTE
(= Note.Vel ofs))
)
)

)
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Then "Save As" ......
File Name = Random Velocity.cal (be sure and use the extension ".cal")
Save As Type = All Files
Encoding = ANSI (I didn't use the option)

Place the file in the "Sample Content" sub-directory located in your SONAR 2 or 3 directory (or in Cakewalk Pro Audio 9 folder - I ran it on both) .

To run the program I selected 18 notes, then
Process->Run Cal...Random Velocity.cal click Open
Enter max. velocity value: 65 click OK
Enter min. velocity value: 55 click OK

I got
60, 62, 60, 58, 64, 64, 60, 62, 58, 62, 64, 57, 61, 59, 58, 60, 60, 59
I think it’s cool.