We are doing the same. We are a small shop of only 3 fox programmers working on a 15 year old app with over 180 tables and about 25 grids. We carved ours off in pieces since we could not be down for over a year without one major and at least one minor release of our revenue generating app.

The first piece done over just short of 2 years was to dump all frx reports and convert all grids and report etc. to views. First we went and made every grid data source and report data source work from the same view generator. We could do this because we worked hard at making the app data driven. All grids and reports call the same process that builds a view ( Cursor Adapters ) and returns it as the data source. In the case of grids we hook to the updateable view and in the case of reports we write out our definition, meta data, layout and data ( view ) files to XML files and call a C# dll that we pass the name of these files to and it build the report display. We were able to drop over 180 frx files compiled over 15 years and use one C# class to do the same work. The old report cursors were generated by over 120 classes and various prog files and is now handled by only 3 classes and one modest very abstract code library that builds views.

The cycle we are in now is to drop the fox back end and use the same view logic to hook to Sql Server. We do inserts and deletes manually and refresh the views and handle updates in the view. 1 year project. This was made simple by the the first iteration. We have an seamless data conversion that was written in fox ( using some Stonefield ) that handled our database upgrades. That will be written into a C# process ( with a just a small amount of fox preprocessing ) to convert the fox data to the server.

The next step will be to convert the UI and middle over to to hook to the view engine. 18-24 months.

We started in 2007 and plan on being fully converted in 2009-2010. We have still been able to release new products to meet our contractual and income needs.