Wallingford Bikes and Rene Herse Cycles both offer 6-month return policies on the Brooks and Gilles Berthoud leather saddles they sell.

http://www.wallbike.com/catalog/saddles
http://www.renehersebicycles.com/NPP%20Saddles.htm

I have plenty of experience with several Brooks models, and my slotted 10-year old titanium B-17 is fabulously well broken-in and consequently very comfortable on the bike with bars just above seat level. However my old Team Pro and Swift don't suit my rear these days. OTOH, my 24-year old daughter loves her Team Pro that's much older than she is. My relatively new (and more expensive) Gilles Berthoud titanium on a slightly more aggressive bike is rapidly gaining ground on the B-17 for comfort, and it's unlikely to need that return policy. It also seems to need less nose-up adjustment for me compared to Brooks. It has VERY thick leather, so I expect it to last a long time with proper care that I don't mind doing once or twice a year on leather saddles.

One other leather saddle that that is worth mentioning is Selle An-Atomica. They generally come slotted, have very long rails which avoids the rearward adjustment problem that some have with Brooks, and many think they are very comfortable right out of the box.