The MrLrS at .150 would be the best for what you descibe. 4" blade and thin like your hunting. They are hard to find and very$ if you do.
The more recent .170 flat grind Meaners can be found, and at a much better price.
The BAD(boney AD) had slim slabs, but is shorter than your looking for. The SAR5 has HUGE scales. And neither is 4" like you want.
The thinest .170 Meaner scales were on the DC/Black g-10. It's as thin overall as my original .150 Leaners, and will slice about the same since flat ground. The 2007 SE Meaner from Blade also had thin scales, but the same knife from the Ganza had thick scales.
A .170 DC/Black g-10 has the thinnest scales, and then the 2007SE(from Blade not Ganza). You can still find them at a good price.
If you want a thinner 4" Busse those 2 would be the ones you want :thumbup: The Black G-10 will have be the thinest scales.
If you really like the hunt, and don't mind paying more an original .150 saber would also be great. It won't slice any better than the .170 flat grinds since the edge is about same thickness.
edit- for what you describe don't buy a Meaner over .170, or one with custom slabs...they are always FAT. And the thiner knife will always slice/cut much better.