the vantages are genearaly considered flexy and allow movement. the new LF Ultras should also allow a good deal of movement, more so than the vantages i think. the shanes too.
hyperlite audio boots
slingshot pb floyds
there are many more.
best bet is to try another store and put whatever boots they have on, walk a bit, wiggle and jump with them on to get an idea. everyones feel are so different. did you try the ronix reliks or franks. they are supposed to be softer. maybe your store doesn't have the full sellection of ronix and obrien both have good stuff for every style of rider