Field cameras choices for you criteria are limited. Shen Hao does let you focus with the back standard. I have been really happy with mine and you almost never see them come up on E Bay or Criags list! There is an alternative call the Chamonix. Also you do see Burke and James cameras occasionally. The Chamonix has received great reviews from those who bought them. The down side is a long lead time to order as there is not stocking distributor here in the US. Shen Hao has distribution in the US from Badger and Mid West Photo Exchange both are very reputable. Keh has a 4X5 BADGER M1 rail camera and you occasionally see the Peter Gowand mini 4X5 on E Bay. Also the Toho Shimo FC-45X is another small rail view camera to consider. You may want to search for a Meredian B which is a knock off of a Linhoff and was made in the 1940's