According to Yusuf Ali's translation, his footnote in relation to surah 2 ayat 275 says that usury includes: undue profit made out of loans of gold and silver, and neccessary articles of food, such as wheat barley etc. It also includes profiteering from all kinds, but excludes economic credit.

In which case, a sharia based economy would work today.

I also took the liberty in reading another translation by Zafar Ishaq Ansari. His footnote says that their is some unsoundness of this verse (sura 2, ayat 275) since it doesn't differentiate between the profit one gains in an investment in commercial expenses (which by the way IS allowed!) and interest. He then goes on to mention that proponents of this view argue that if profit on money invested in a business enterprise is permissable, why should the profit accruing on loanded money (interest) be deemed unlawful.

I had a look in my book of Sahih Al-bukhari hadith with regards to usury/riba, but was not able to find any more meaning towards it. So for now, I think Yusuf Ali's footnote seems most suitable, since it would explain why the Islamic economy (at the time) did not falter, seeing as interest is a core part in economics and business - something that arabs at the time were well adapt with.

p.s; the Yusuf Ali footnote I used was condensed; the full version contained the passage that Gator [see two posts before this one] gave.

p.p.s; Thanks Ahsan28 for the link - will be reading that ASAP!