LTSP-Cluster is a set of tools and plugins for LTSP that allows you to extend LTSP so that it can scale up to hundreds of servers and thousands of LTSP clients. It has a nice web interface for your LTSP configuration, does load balancing between your servers and more. It can even connect your LTSP thin client to a cluster of Windows terminal servers or NX servers, if you’re into that sort of thing. If you’re deploying LTSP soon, you’d probably want to investigate LTSP-Cluster, and I’m not just saying it because I’m involved in the project :)
It’s licensed under the GPLv3 license and supported by the LTSP community, you can also get commercial support *wink* *wink* from Revolution Linux where plenty of very skilled people are ready for your LTSP related needs.