Yes. Most new cars, including Saabs, can be ordered with a factory installed
multi fuel option.
 (I will stick with my '79 96 on LPG though)

At the SOC in Belgium I talked to mr Martens, of http://www.saabmartens.com/ who
was there with a 900 turbo on LPG. No problems he said.

It is the type of LPG install that is the problem.
It is doable though. Latest spec LPG installs use a seperate set of
injectors, and their own ECU and a "bypass" to fool the factory ECU into
thinking it is still working.

Older systems just used something like a carburetor to do the same
thing, and just tricked the ECU with the readings it was getting, rather
than bypassing it.

The C900 turbo, and all FPT 9000 models are too advanced for the
"Cheap" LPG conversions that tend to be setup for carb and early
injection systems. Later models need modern setups. It just need a more
careful setup of fuel to air and monitoring with LPG.
You can even get vehicles that can run 100% of the time, even at startup
on LPG, because the system pumps it as a liquid into the engine instead
of petrol.  Once started it returns to pumping it as gas, and the engine
runs as a normal LPG run.