That said, check out this guy's work... it really is quite beautiful.
Steampunk Flat-Panel LCD Mod | The Steampunk Workshop
A friend directed me to that website a year or so ago, and I've been lusting after something like that computer ever since.
I think the point that some of us are making is that some things are incompatible -- they require different world views for instance, as well as different levels of technology. But I would modify that a bit to say that if you
do combine them you need to have a mighty good explanation and a mighty convincing rationale behind it. You can't just throw them together because you think it would be cool, or because you think it would suit the kind of story you want to tell.
However, looking at this part of the first message
1. Is it possible for both a culture of steampunk and a cyberpunk culture to exist within close proximity of each other? If not, what would be a good distance ( in relative terms) in which they could exist?
I think you could manage it. Because right now, right in the midst of our technologically advanced society, there is another society that chooses to function at a much earlier level of technology, and has continued to do so for a long time, and will continue to do so for the foreseeable future. Think Amish.
So
if your Steampunk society has some very strong religious, ethical, or philosophical objections to the beliefs and the lifestyle of the Cyberpunk society, and
if you can work out what those are, and make them a real part of your plot, examining all of the consequences past and present within the world of your story (instead of just dropping them in as an explanation and leaving them untouched afterward), and
if you do this thoughtfully and skillfully ... it's possible you could make it work.
The big question is whether this might not involve more time and effort and research than you were planning to put into it.