Here's a link to a thread w/ pics of the inside.
(scroll down a bit)
http://forum.purseblog.com/louis-vuitton/the-batignolles-club-15188-2.html
These pics helped me out alot when I bought mine just a few days ago. I was scared the bag would be too big. But it's a nice size, roomy (not too overwhelming at all). I noticed I can take alot of things...or just leave some other things behind and it's still stays partly filled yet with extra room but not empty looking.
This is what I carry in mine: sm. wallet (LV Ludlow), Pochette accessoires, ckbk., LV sm. agenda, sm. brush, hairclip, ph (in cell pocket), magazine (laying across), knitting ball of yarn.
I can easily leave behind the magazine, knitting ball, hairclip, brush...and just carry my wallet, ckbk, agenda, pochette and it's fine.
Here are some more links re: BH. I read all of them when I was deciding. Helped alot. I am THRILLED with my BH!

I was scared of size too. Didn't want my things drowning in it. When I saw it IRL...I looked at it, tried it on, that was it...I knew.
There's comparison pics on this thread w/the piano, and mezzo to get an idea of size.
http://forum.purseblog.com/louis-vuitton/bagtignolles-or-cabas-piano-poll-10138.html?highlight=cabas+piano
Here's a link to site w/ inside pics too...
http://www.rakuten.co.jp/beltempo/430749/431825/452632/608963/
More pics..
http://forum.purseblog.com/louis-vuitton/batignolles-horizontal-any-pics-6566.html?highlight=Batignolles+Horizontal
Besides all the pics all the posts are helpful to read as well.
Btw, the bottom (at the base/across) measures 15.3", but at the top opening it's about 12 1/2".
HTH! GOOD LUCK!!!!!!!!!!! Let us know what you decide!
