Scale - 1:12. This is where my wife and I have had the most talks.
First, we were looking at playscale, because chances are barbies will be
used in the dollhouse at some point. However, I prefer to not focus on
the barbies, so we moved to 1:12. Then we looked for dolls that fit this
scale, and we didn't really find any (it wasn't a very big search
though). There seemed to be several popular choices that were just under
this scale. So for a bit I went to a strange smaller scale (I'm not sure
what it would have worked out to, and don't want to do the math right
now). But after doing the reading of archives, and actually thinking
about little hands being able to reach in, etc., we ended up on 1:12. We
will still probably go towards furniture and dolls that are just below
that scale, but the house will be built to accomodate the wide variety
of toys that will hopefully be used with it (my sister's dollhouse saw
home to small dolls, barbies, star wars figures, transformers,
hotwheels, and so on).

We do 1:12 scale dolls, furniture and accessories that have all been
safety tested for children (CE in Europe, ASTM in the US) over 3 years
of age.
http://www.dollshouse.com/asp/junior.asp?siteID=US

Hope this is useful to you and good luck getting this ready in time
for xmas...

Paul
http://www.dollshouse.com