Agree with Gregorio. Your basically looking at 20% down for an investment property with the lone exception being a Homepath Investment property loan (must be a Fannie Mae owned property for Homepath though).
Tom - I don't know of many 'generous' private lenders, unless you generous means offering 60% LTV at 12% - 14% interest rate!
No, the best you can do is 90% and only on a property that qualifies for HomePath financing; otherwise you will need 20% down. (Note that putting 25% down saves you 1.25 points in fees, but is not a requirement for investment properties)