Sri Lanka'a GDP in 2008: Approximately $41B (page 16 of 2008 annual report)
Italian Mob annual revenue (2008): Approx. $167B.
LTTE's annual profit (according to Jane's Defense) in 2007: $200-300m. I remember reading somewhere that it was $300-400m but can't find the reference. Assuming a profit margin of 20%, that's at least $1.5B annual revenue.
Walmart 2008 revenue: $401B.
IBM 2008 revenue: $104B.