I have been working on a Active Directory tool that makes it easier to work with users from another AD Forest. My main goal was to improve upon the horrible search function in dsa.msc by allowing free text search in real time (WinAmp “jump” style is the best example I can think of). I also did not want to have to enter credentials more than once, and to have an easy way of querying the Domain Controller in the foreign domain for basic information.
I found that you can easily create a GUI interface for PowerShell using Visual Studio, so I started to poke at it. While not complete, the add/remove functions are currently working. I have tested this in an environment with about 2000 groups, and while it does take a few seconds for the groups to enumerate the searching is fast and responsive. The tool only appears to run on Windows Server 2012 R2, not sure if just .NET is missing in Server 2008, or if the default version of PowerShell is too old. Anyways, you can find the latest version of the tool here: