I am actually pleased that today we have a bit of variety in tools that can generate BDC Application Definitions. An addition to this list of tools is "MOSS BDC Design Studio" by Simego, which actually quite good and easy to use. The site offers a 14 day trial version, and prices aren't that bad (but me thinks it should priced more a little bit more reasonably). But still for all the tool is quite good, it seems to be limited to SQL Server and WebServices which is a limitation. The other limitation...