Some Leathermans have blades with guthooks on them. They're at the expensive end of the Leatherman range, though.

I've used my Victorinox pocketknife to skin rabbits and a cat - you tend to get hair and and other, wet gunk in the hinges and the handle - which can be washed, but it takes a while for the knife to dry because water collects in the hinges and between the layers. With a fixed blade you just wash it off and quickly dry the knife with a towel - there aren't inaccessible crevices that collect water and debris.

Leatherman uses a kind of stainless steel that is harder than the cutlery steel used in Victorinox knives, but more susceptible to rust. Given that skinning the animal and washing the multitool after are wet activities - plus you might be salting the skin to preserve it - I think Leathermans aren't ideal because of the rust issue. They're good as an all purpose tool, but a dedicated, fixed blade knife for field dressing is worth the extra 100 to 300 grams in the backpack in my opinion. If you must have a multitool to use for field dressing animals, my recommendation is Victorinox because the steel, although softer, requires no maintenance at all to prevent rust.

I don't have experience with dedicated hunting multitools with a single hilt and several interchangeable screw-in blades - however they don't appeal to me because they seem to lose the convenience you get with regular multitools (ie: quickly accessible variety of tools in a small, light package) and sacrifice the strength that would be afforded by a full tang, for only a slight weight advantage.