I posted a similar question a while ago but needed more customization.
I used SVG path data in Degrafa to create custom maps of the world, continents, USA.. for a customer. Degrafa used to have a nice US map demo (with source code) as part of its samples, but it disappeared from the web. I don't know of any tool that would help to design clickable Flex shapes. I have no doubt though that Degrafa will provide more support and tools for converting and using SVG.
Some products I found: ilog, ArcGis
And also found this open-source library : GeoVis (birdeye)
But it's very unstable and haven't seen many changes recently.