Bashiok replied to a post asking about a shared stash in Diablo 3. Here’s the quote:
No update, it’s something we hope to do, it’s not designed or in any sort of implementation phase so until we reach that point and either hit a revelation of it working or not we won’t know for sure. But yes, still hope to have some sort of easy way to share between characters. “Drop games are dumb.” – Bashiok
This is good news, of course, but it also serves to show just how long games take to develop… Jay Wilson gave essentially this same answer in Blizzcast #5, back in August 2008! Quote and link on the Stash page of the wiki.