I spent some time over the weekend porting the AS3 Vector.<T> class to C# for use with Silverlight. It uses System.Collections.Generic.List<T> as a backbone, so it leverages a lot of the existing functionality, but the main purpose is to keep the same method signatures as AS3.

Source: hhttp://github.com/mbolt35/OpenSource/blob/master/silverlight/Bolt/CSharp/Collections/Vector.cs

This class would most likely assist in porting large AS3 projects to Silverlight, depending on how much Vector. was used in your AS3 application of course :)

Code is written under the Apache License - Enjoy!