Jojo Mendoza (released under a Creative Commons License):

I've put together a Windows .ico file and dosbox_logo.h file that can be used in a custom DOSBox build; the .ico and .h file are in this zip file:
http://dl.dropbox.com/u/271144/DosBox-CPrompt-icon.zip
I learned how to create the dosbo_logo.h file from messages by @ykhwong and others in another thread in this forum:
http://www.vogons.org/viewtopic.php?p=206046