Question : Hig-latency networks and MS file transfers

We have a high-latency WAN connection (MPLS), with 40Mb/s bandwidth. Depending upon where in the world the two endpoints are, the latency varies between 50ms and 600ms.

File transfers using Windows XP / 2000 systems is limited to 3 Mb/s between North Americ and Europe because of the 120 ms latency. With a protocol sniffer, we see about 50K sent in 3 ms, followed by a 120 ms delay while it waits for an acknowledgement.

I understand the limitations of SMB and that SMB2 in Vistal addresses high-latency WAN connections. I've set up a packet shaper (Linux kernel and MasterShaper) to demonstrate the problems in our lab. So I have 3 questions:

1. What kind of improvements have people seen with Vista?
2. Has anyone come up with tweaks to Windows to improve the performance?
3. Is anyone using alternate protocols to share files to address this problem (ie. NFS)?

Answer : Hig-latency networks and MS file transfers

Two solutions have worked in the past:
    http://www.asperasoft.com/technology/index.html
    http://www.rocketstream.com/home/default.aspx