I beleive that was was based on a Suzuki mini-SUV from back in the 80's
don't know how yer getting Omni/Horizon out of that (?)
..unless yer thing of the Dodge Rampage, which had the front of an Omni 024..but the rear of this is totally different..way too short
..and I beleive HW did do a Rampage cast...I'm thinkin it had a motorcyle in the back (?)
one other factoid.... this cast was done as a Final run, I think around 2000... probably could be found on evil-bay, if ya look hard enough.... if u want a nice version of it....
was called Gulch Stepper