Yup, Islamic Banking 101 ... needing to find Allah approved ways around the concept of the riba - which encompasses both usury and interest, makes for some interesting financial products :). The basic idea of Islamic banking is to spread cost / profit / loss around in a shared manner.
Although definitely not a very efficient instrument from classical capitalist POV :)
Just so long as these "devout" Muslim don't get the tax deduction on interest I'm happy. This home buying system claims no interest is charged and it damn well better be honestly run to where they lose the tax deduction. I hope they buy automobiles the same way.
(actually they are paying interest but it's built into the lease payments)