There would be no authoritative answer for the "is it theoretically possible?" question unless it has been done successfully by someone.
Although ESX and Hyper-V do share some concepts about snapshots (virtual hard disk contents are frozen in time, a copy of the RAM contents and the states of virtual devices and virtual CPUs are saved alongside), the implementations would be vastly different. The fact alone that Hyper-V and ESX use different kinds of virtual devices (NIC, HDD controller, graphics card) would prevent any kind of simple transition among them.
If you are only aiming for the contents of the virtual hard disk, things would be easier, but not without difficulties: Hyper-V does not store snapshots in files but uses Windows Volume Shadow Copy for point-in-time freezes for the data, so any converter utility would need to be able to handle that.
All in all, I doubt that anyone would consider the necessary effort worthwhile and write something like that.