CNC router power

(Just to clarify im talking about the english system for mains voltage) What can I use for a power supply to output between 12-30v at 8-10amps (this is for a stepper motor control board) and also out 7-12v (yes this is for an arduino).

Some information:
I am building a cnc router utilizing a dremel or rotary tool as the cutting tool with a synthetos gShield as the stepper control board and running the code on an arduino. These three things require different voltages, the dremel can run of mains power, but the arduino needs 7-12v (as im sure your aware) and the shield need 12-30v with a lot of current each winding can supply 2.5amps so in total 7.5 amps may be drawn so about 10 amps should be sufficient .
Any help would be great.
Would a PSU work?
do i need to build my own power supply?
and what about smoothing circuits or fuses?

Cost wise, maybe something like this ....
If you need variable then maybe a bench power unit but big bucks there.....
Your arduino could be off seperate supply, plenty of those around.

I want to run everything on one wire (two socket extension lead) on socket would power the dremel and the other would power both the control board and arduino. Where the control board has roughly 12v 8-10amps and the arduino has 7-10v.
Would a psu work where two 5v lines are wired together to produce 10v, and the 12v straight from the line off the psu. Would that give enough current.
Would a psu supply enough current? (10amps)

Now I'm really confused as to what you are trying to do.
Best to draw a diagram.

run your mains power into your box.

but the arduino needs 7-12v (as im sure your aware)

no, not aware of this. I power mine from 5 volt on the USB or 5 volt regulated on the raw input. Run a switcher for the 5 volt for the arduino. you are not required to use volts if you have a decent regulated power at 5 volts.

run your 12v transformer from the mains for your steppers.