I have seen the introduction of Longhorn 4050 in a Chinese soft site. It is said it was been built after 4051.

Version:
build 4051.idx02.031001-1340
build 4050.private/lab06_demo.031019-1809

pdc.xbetas.com has some info about Longhorn from their visit to PDC 2003. Have you noticed that in 4050 there is some new icons?

What a pity! I havn't got one and know nothing about 4050.
There is something about it on xbetas.com(http://pdc.xbetas.com/content.php?page=4050)

It is obviously internal as I haven't seen it anywhere else, so who knows whats under the hood.

it also has a bleu slate theme
i really want it lol

I am expecting the first beta version.