Don't know about the forward flap....but I LOVE my older Prestige Professional. I have sat in the newer ones and they just don't feel the same to me. Mine has a very shallow seat (matter of fact, most of the barn hunter folks have loved the feel of this saddle)
ha!! That's exactly what I'm looking for minus the forward flap (already got my jumping saddle)!
I have fallen in love with an old Stubben!!! It's the Romanus dressage saddle. It's got a wide gullet and fits big ol' wide Fleck beautifully in the back, it's got a narrow twist (or atleast I'm assuming since it's very comfy for me!) and is flat. I have a big ol' giant ghetto booty and the badonka donk pushes me forward and makes me perch in those deep seats with the high cantels! The stubben is flat and comfy
Maybe try looking at theirs... it seems like I've seen some all purpose type ones that might be what you need. Plus.. they are usually on the cheaper side
How about a Euroriding Diamant VSD in a treesize 4 (maybe 3). ( size 5 is seriously wide..., as in xx-wide). But, no interchangeable gullet unfortunately.
Even a tree size 5 still feels narrow in the seat, so no worries there, seat is medium deep, not totally shallow.
Don't remember the website, but you can get them new in the US for around 1,5k. I wished I found that website back....