The reference implementation is in VisualWorks, but work has been done for VisualAge, Squeak, and others. Although clients don't have to be in Smalltalk, when they are, it is easy to move functionality between clients and server. GeoSynchrony GIS framework. You can try before you buy.
Documentation is in Spanish or Portuguese.
BFT Report Builder is a visual tool allowing the developer create reports graphically. It appears that this package will no longer be produced. File Reader is a framework which enables you to read all kinds of files. Gemstone has a non-commercial version of their server for Linux that works with VisualWorks. Glorp is an open source object-relational mapping layer.