well, we have at least three such merges already made...

I created a merged template between the AkoWinter mambo design and the loon-blue SMF design...   called it Winterloon.

Someone else did a merge for SMF with the Planetfall mambo template (which was unchanged)

And one other one was made... can't recall which.   

There's a thread on this on the SMF mambo discussion forum.

It should be noted that sharing the Stylesheet files, etc is not a great design idea, for a couple of reasons. The two biggest reasons are: 1) not everyone has the saem setup in terms of directories, etc) 2) if you upgrade mambo or SMF, it could screw things up

So, I think what we've don so far...   designing smf and mambo templates to work together under their own base design (in other words, use the standard directory structure and duplicate things where needed) is the best idea.

personally, I hate fixed width templates.

however, there will never be a single template that can be used across the board.  everyone wants something a little different.

I actually think a better idea would be for someone to deisgn a mambo template that uses the default SMF Theme look and feel...