Is it possible to replace Excel's VBA Editor/IDE with a modern alternative? [closed]
You might consider using VB.NET instead of VBA for your Excel development. Excel-DNA (which I develop) is an open source framework for integrating .NET in Excel, which tries to make the VBA to .NET conversion as easy as possible.
Then you can use any editor for the VB.NET (or C#) code, including the Visual Studio Express editions or SharpDevelop.