The demand to fly cargo and corportae, as you say, is just as high as the demand to fly for any passenger airline. Competition is severe for ANY job thats going. Whether its a large jet or a beat up old turboprop on night freight, there are 1000's of applications posted to companies every month.
At the moment, the industry is going tits up due to high oil prices and ecenomic recession. The future for any budding pilot looks extremely bleak.
Anyone contemplating undertaking training is taking a massive gamble. Save your money and stick to flying as a hobby. Just my tuppence worth.