The problem with this is that the emoticon code is wrapped in tables. Even in the php code to some extent, from what I saw.
The weblog stuff is *not* wrapped in tables, unless you add it. Especially not in the php code (unlike the smilies) - and so having this feature would be confusing and difficult to implement and not confuse a lot of people.
MT has a plugin called MT Grid which forced iteration of entries over a table. You might put in a plugin request for someone to try to mimic that here. I can see that being useful for photoblogs etc. =)
