Saddle help

[ironhorse]

Any ideas for saddles for horses with massive back muscles?!
Our QH mare has dramatically muscled up in the past 6mths and is in western training so she has massive muscles over her back and loins.
After a few probs with her English saddle, (an Ideal VSD, wide fit) we had a long session with the trainer and a master saddler who ascertained that the saddle is being kicked forward by her movement, particularly on a curve, which makes it sit on the inside shoulder leading to rapid brake-slamming and napping.
The saddler, who is pretty stumped by the problem - I guess most people who have good western horses aren't awkward enough to want to ride them English as well - is going to try and tweak the tree in a fraction to see if it will hold the saddle in place better.
But I would love to hear if anyone has similar experiences - if not with a QH perhaps with a cob or native in hard work, or a ride and drive horse. If we can't get this saddle right, anyone have any suggestions? Treeless, endurance etc - needs to look fairly conventional as I'd like to do a bit of dressage and her breed classes require a 'hunting type' saddle.

 

[Darkly_Dreaming_Dex]

Unfashionable solution!
I have seen a QH with this problem and the owner found that the County brand of saddle (English made but very popular in the States, the GP was called the Competitor) worked well as it scoops up at the back (gathered panel)thus clearing the muscle area rather than having the modern gusseted panel that can result in the muscles hitting a vertical barrier.So when my cob went through a bucking phase coupled with developing a bulge in the muscle behind the saddle I tried every type/brand of saddle i could get and cured the problem by using a vintage Adams Podhajsky saddle.(still in my loft) I now use an ancient stubben which due to its age has a lovely soft squashed flat panel to the same effect. I have tried going back to the modern styles but the problem returns.