I've been using SharpDevelop for editing the XSL and Javascript files, instead of Visual Studio 2005. I found the syntax highlighting and XSL code completion greater on the former (and it's open source/ free). I also added a fantastic little Addin to Sharpdevelop which counts the lines in all the files.
The original GMap.Net Control, written by Bill Pierce for Google Map API v1, has around 2 KLOC (thousand lines of code). My work so far on v2 (and I only properly started 7 days ago!) has brought that up to almost 6 KLOC! Most of that has been very repetitive copying of the Google API, and copying and pasting from v1 so I'm not going to rest on my laurels just yet. Especially as it doesn't work!

Still, it's a great little feature on SharpDevelop.