[K12OSN] Sanity check needed before rollout

[john]

Hi all,

I hope folks can give me a sanity check before I begin a large scale
(35 client) roll out at one of our schools this summer.  First the
scenario, then the question. I plan to setup a robust server LTSP
server, with /homes stored centrally on different "backend" server.
This "backend" server will provide authentication for LTSP clients via
LDAP, but users will be drawn from Active Directory using SAMBA to
integrate with our existing domain. Windows users and LTSP users
network share should be accessable either as \home while on LTSP or as
a network share when using WindowsXP.


Hardware

35 thin clients clients
1 LTSP server (2 duel core opteron 8100, 8 Gigs of ram, Edubuntu 7.04)
1 "backend" file server doing NFS, SAMBA, LDAP and Webdav, 3 Ghz
workstation with 4Gb ram (Centos or Ubuntu LTS 6.06)
1 Dedicated Gig E switch

Software/networking:

1. The LTSP server will authenticates clients via the LDAP backend
server. Users home directories will be stored on the backend server.
2.  The LDAP backend server is joined to our Windows AD Domain, via
winbind and linux user accounts are automagically created via SAMBA
which stores account info in LDAP per
http://us4.samba.org/samba/docs/man/Samba-HOWTO-Collection/idmapper.html#id369912

My question are:
1) What am I missing, forgetting etc?
2) Is my authentication scheme nuts? I can't dump Active Directory,
but is there a better way to do this?
2) Do I need a "real" server doing RAID 5 or whatever for the LDAP Backend
3) Am I REALLY off base with my proposed setup?

Many thanks for any and all ideas!

John