what size would this .iso be? and what should be in it?
what size would this .iso be? and what should be in it?
you should go to www.ltsp.org and read about what's needed for LTSP and PXE booting.
It's size will mostly depend on what you want to boot and what you want to do on the PXE booted clients.
Off the top of my head, LTSP uses, DHCP3, portmap, DHCP, named, NFS. IT needs a boot image( currently about 4MB ) and then a runtime image( you decide the size ).
pxes.sf.net is also a good one. They now also support cd-rom booting, afaik.

TP-Link TL-SG105 5-Port Gigabit Ethernet Unmanaged Metal Desktop Network Switch
$19.99
Cisco Catalyst 2960-48TT-L 48-Port Fast Ethernet Managed Rackmount Switch
$46.99
NETGEAR GS308EP Essential Series 8-Port Gigabit PoE+ Unmanaged Switch
$49.99
TP-Link TL-SG1048 48-Port Gigabit Rackmount Switch New Factory Sealed
$199.99
5 Port Gigabit Unmanaged Ethernet Switch, Home Network Hub, Office Ethernet S...
$9.64
10-Port Gigabit PoE Network Switch with 8 PoE+ Ports with 2 Combo SFP Slots 125W
$39.99
TP-Link TL-SG2210P 10-Port Gigabit Smart Switch w/ 8-Port PoE+ NO AC SKU 25597
$36.98
TP-Link TL-SG105, 5 Port Gigabit Unmanaged Ethernet Switch, Network Hub, Ethern
$15.25
Linksys LGS328MPC 24-Port Managed Gigabit PoE+ Switch with 4 10G SFP+ Uplinks
$224.95
Cisco WS-C3650-12X48UR-L 48-Port Stackable Layer 3 8x10G SFP+ Port Switch
$129.99