I published two Smart Client articles. I hope these might be of your interest:
.NET 2.0 Smart Client + .NET 1.1 SOA based Services
http://www.codeproject.com/smartclient/smartclientsoa.asp
A RSS Feed Aggregator & Blog Smart Client
http://www.codeproject.com/smartclient/rssfeeder.asp
This MSDN article of mine will help you understand the architecture I have followed:
Implementing Word-like object model for your .NET app
http://msdn.microsoft.com/smartclient/default.aspx?pull=/library/en-us/dndotnet/html/automationmodel.asp
Use "Disposable" COM without using interop assembly, late bound and strongly typed and version independent:
http://www.codeproject.com/csharp/SafeCOMWrapper.asp
And finally a new pattern I proposed, Distributed Command Pattern:
http://www.codeproject.com/csharp/distributedcommandpattern.asp
Hope you enjoy them.