[K12OSN] Multiple server setup

[Krsnendu Dasa]

I would like advice how best to set up my multiple servers to run 
different applications.
At present I have a low end IPCOP machine running Dansguardian.
I also have 2 identical AMD 2500XP machines GB Lan. One of them is 
running K12LTSP 4.2.1 (about to be upgraded to the latest v5.0.0)
The other one was used as a Windows Xp machine for multimedia/design.
I have 3 identical hard drives 120 GB SATA: One has got WinXP on it. One 
has got K12LTSP 4.2.1 on it. The other one is free.

Options:
I was thinking of keeping one as K12LTSP and the otherone as backuppc 
server on Ubuntu.

I also want to use asterisk,Koha library software and a bell automation 
software. Should these also go on the K12LTSP server, or will it hit the 
performance of LTSP?

I was also thinking of install VMserver and running asterisk and 
backuppc as virtual machines any advice?

Also would putting /home nfs mounted on another server improve the 
performance of K12LTSP?
I am considering getting a bigger HD for backup (also have a few WINXP 
laptops to backup)
I am also considering another server if necessary.

Thanks.
Krsnendu dasa