Although quite academically this is an interesting article.
http://research.microsoft.com/pubs/167719/WhyFromNigeria.pdf
Basically, the aim of the scammer is not to make the most believable scam he or she can, but to make the scam as unbelievable as possible to sort recipients and make sure only the most gullible (and hence most likely to part with actual funds) respond. This then means less effort needs to be expended on actually getting cash. The scammers aren't as dumb as we think.
http://research.microsoft.com/pubs/167719/WhyFromNigeria.pdf
Basically, the aim of the scammer is not to make the most believable scam he or she can, but to make the scam as unbelievable as possible to sort recipients and make sure only the most gullible (and hence most likely to part with actual funds) respond. This then means less effort needs to be expended on actually getting cash. The scammers aren't as dumb as we think.