Okay so Oscar was a stray that my clinic took in 4 weeks ago, and now he has
been at our new house for a week.

During his stay at the vet, he has had THREE fecal flotations done, all of
which came up negative.

I have always noticed that his belly is bloated and distended.  It is also
very hard to the touch.  The vet has classified it as "M1 distention"....
which I think means mild.... but his belly is still like this and it hasn't
gone away with time.  He has been treated with Revolution a month ago and
also with a general dewormer (Drontal).

As I said earlier, he has had a series of 3 fecal flotations done.  One when
he first got to the vets, one two weeks later, and one less than a week ago.
They all came up negative.  I'm considering sending a fecal sample off to
the lab to have an ova and parasite run on it in a couple weeks.  I'm
suspicious he may have coccidia which I know can be notorious for false
negatives in the flotations.

The vet doesn't seem to have any suggestions except to continue to run more
tests on his poo.  Visually, his stool appears completely normal (in colour
and consistency).  Although there was a couple times when it was lighter in
colour, foul bitter smelling, and appeared to have pinhead white dots in it.
I took a sample of this stool for a fecal flotation = negative.

FIV/FeLV testing = negative
pre anesthetic blood panal = all values within normal range.
He urinates completely normally.

Does anyone have any ideas as to what could be causing his hard, bloated
belly???