re:netboot -- this is a linux example. (i never used netboot, it's probably wildly structurally divergent from nfs-mounted home dirs. anyway)
i'm running 34 fah clients from one home dir (i have a .fah folder and 34 fah# folders inside it).
my home dir is mounted by the machines automatically when needed (nfs). so basically, my home dir is mounted on 17 linux boxes full time.
i thought of running on local drives, but it's so much easier to keep track of the linux boxen this way (since they don't run web servers, i can't do the 'ln -s' into the web dir trick i use on the macs to make the fah data more available remotely. i can run shell scripts, aliases and cron from any one linux box (like mine) and process data for all the procs. (i still had to rsh and set up 17 crons to do the actual fah start scheduling on each machine)
each proc has a unique id because i set them up individually (i make the dir, copy the client binary only and then run ./FAH4Console-Linux.exe -local -configonly and set the crontab for each proc)
RE:HD Access -- i think uptime and sleep/no sleep is a personal preference. i've had machines running for years with no failures - but sometimes not (i do back up my home dir nightly now).
my dual 500 G4 has run 'continuously' for 3 1/2 years. it's been running fah 24/7 since early december at full bore. the G5, too. and my work mac. in fact, work macs are not allowed to sleep. well, either are home macs. and i run them all hard, all the time. i'm sick.
here's the g4's uptime - i added some software updates recently, but you can see each proc is fully utilized and it has been up for 12 days.
bat:~ admin$ uptime
18:32 up 12 days, 4:54, 2 users, load averages: 2.00 2.00 2.00
before you accept my word, remember that i'm not afraid to lose _some_ data, i do back up alot of stuff and frequently, and i do all my own hardware swapping/repairing. historically, i've constantly had to reinstall my OS on my main mac because i get too jiggy with the cutting edge stuff. (yet the replacement G5 apple gave me has somehow survived all my schemings so far - knock on wood).
- hope this is of some good to you.