I'm in a similar boat to yourself, looking to move to medium format although for slightly different reasons. You may find this thread of use: http://www.apug.org/forums/forum51/8866-opinions-pentax-67-mamiya-c330-landscape-bang-buck.html it started as a comparison of two cameras but has since evolved into a look through a lot of people's experiences of a wide range of MF and LF gear. I also stumbled on this rather wry article, which I am personally taking very much to heart at the moment! http://www.largeformatphotography.in...ic-bullet.html
As far as slowing down, I currently shoot with an F80 which is nearly as easy to shoot quickly with as Suzanne's F100. However, I find a tripod with a good three-way head and a cable release slow me down quite well and make it far easier to peer around the edges of the 'finder prior to making the shot.
Whatever you decide, all the best with your choice.