To what degree do fetishes differ from conventional sexual orientation? If a person can develop - through some function of psychology/imprinting - an explicit attraction to some object (objectophilia - and in some cases, such individuals go so far as to have fully expressed relationships with such objects), then is it possible for a homosexual to develop a 'fetish' towards members of the opposite sex, or similarly a heterosexual towards members of the same sex?

Furthermore, how would such an attraction differ (if at all) compared to 'non-fetish' based sexual orientations such as individuals that identify as bisexual? Or would they appear, at least superficially, indistinguishable?

https://www.youtube.com/watch?v=GcI4fyfI1WM (documentary of a men that fall in love with their car)

EDIT:

I was reading different studies on the whole, "nature vs nurture" debate regarding homosexuality - controversy aside, it sparked the idea that perhaps, like paedophiles who become infatuated with children etc, whether its possible for a person to become (through some exceptional circumstances) infatuated with members of the opposite/same gender, even if they would not otherwise be considered as bisexual. 

My point being, if someone is able to become attracted to cars in early childhood, that we can easily label as a fetish because of its context: is it therefore possible for a naturally gay person (or otherwise) to become infatuated with the gender which they would not otherwise be attracted to, because of the similar circumstances that, in my described example, would drive a man to fall in love with his car – and would we be able to identify this as such. (In short becoming 'bisexual', but perhaps superficially)

(Ps - for the people arguing over my use of the term "fetish", I do not presume to be an expert on the subject, and frankly wouldn't want to :), but seeing as people can be attracted to objects: objectophilia, animals: zoophilia, children: paedophilia, etc, it seems to me that just because the opposite gender doesn't fit into an accepted category as a "non-genital body part", it couldn't occur under the guise of bisexuality. And, as one comment so enthusiastically assented, "Anyone who has an attraction to both sexes is bisexual," which is what we all assume, and yet, should my proposed hypothesis be true, this might not be as straight forward as it is intuitively understood.)
By Wikipedia's definition a fetish is "a sexual fixation on a nonliving object or nongenital body part."

So, no, it is not 'possible' for anyone to develop a 'fetish' towards a living object.