[pointyhats]

To be honest I dragged a 1.5MLOC .Net 1.1 Web Forms and SQL 2000 application up to 4.0 and SQL 2008 R2 last year.

It wasn't that much of a problem. It took about 3 days and most of that was fixing deprecation warnings and porting the in house test framework to NUnit.

The real problem in the process was getting the build tooling and all the associated crap surrounding the solution up and running. This was also only because the muppets who wrote it originally put it together with sticky tape and string.