What i wanna make is a plasma cnc cutter really
that will probably make life much simpler :)

I'm no expert with plasma.... the drives you linked are quite low voltage and may not to be quick enough for plasma

you may be ok with 50v drives if your machine is light and nimble or to play it safe 80v drives

CNC Wantai Digital Control 4Axis Stepper Driver,24-80VDC/7.8A www.wantmotor.com | eBay


for linear rails and ballscrews lots of people on this forum use this guy in china (linearmotionbearings2008)
linear rail SBR16-1200mm(4 rails+ 8 SBR16UU blocks),SUR | eBay
have a look through some of his kits to give you an idea of whats available (he will do any sizes you require just email him for a quote)

the touch off and retract should be relatively easy to impliment but i have no experience with arc voltage height control