We have just released a developer toolkit that will make creating activity libraries much easier. This toolkit contains a set of templates for Visual Studio and a PowerShell Converter utility. With the PowerShell Converter you can automatically generate an activity library from any PowerShell snap-in that you have installed. You can download it here:

http://community.citrix.com/cdn/wf/sdks

If you are a part of the Software Developer audience for Workflow Studio you definitely want to check this out. If you have comments or questions you can use the Activity Library Development forum.