My personal experience with these fish is very limited, because I still own juvies right now (2
Osphronemus laticlavius aka RTGG).
So I haven't personally raised one through it's entire lifespan
yet, but I will keep my two around all their lives.
From various posts I've read around the net, I've read 10yrs, although I bet they could live double that.
There are four described species of Osphronemus:
gouramy,
laticlavius,
septemfasciatus, and
exodon, with the latter two being very very rare, if at all ever kept by an aquarist (I don't think they have).
I see you are interested in O. exodon which is an interesting choice (It's very rare, I can't even find distinguishable pics on the net). From my research, this fish is said to have teeth as an adult!
Here's a nice link with plenty of info on O. exodon, including very interesting details about it's teeth:
http://www.fishbase.org/Summary/SpeciesSummary.php?id=26871
Osphronemus originate from Malaysia and Indonesia, where they are native and mostly farmed as food fish (Osphronemus gouramy)
A nice link with specific areas in which Osphronemus can be found:
http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=25130
I have never seen or heard of a piebald morph, but there is a white colored giant gouramy, which is Leucistic I believe?