Help with a Stand Alone Controller I want to build.

Hi, I know a little about electronics and need some guidance on what kind of stand alone controller I can use to complete this project. I'm hoping the Arduino can do this, if not let me know what can do this. I plan on hiring someone to program it for me. Maybe someone here would be interested. Anyway, below are the parameters I'm looking for.

The User Interface will be a small 9” or so touch screen.
There needs to be 6 inputs for RTD Temp Sensors or Thermocouples.
There needs to be 4 to 6 Outputs to control a stepper motor, probably a stepper with 525 oz./in. For this I can use outboard Gecko drives that the stand alone controller can control.
There needs to be 6 outputs for On/Off which will be used with a relay.
The stand alone controller must handle these things.
The screen will show all 6 temps at once and constantly refresh, probably every 1/4 second or whatever is reasonable.
There will be a screen with a touch screen slide to adjust the each stepper motors to a certain position or the stepper motor, which will in most likelihood be connected to a ball valve, can be controlled like a PID using one of the temperature probes. For example temperature probe 4 is measuring water temp that is regulated by a ball valve with a stepper motor connected to output 2 on the controller. I want that water temp to stay at 145F. So the controller will have a simple user interface to set these parameters.
The temperature display when touched will go to an individual screen where a timer can be set for either temp or time. So let’s say I want switch 1 to be turned on at 6:00 am and turn off when it reaches 150F.

If anyone has any ideas I'd appreciate it. Thanks.

The User Interface will be a small 9” or so touch screen.

Forget the Arduino, then. It has no where near enough memory or processing speed to drive that size display.

small 9” or so touch screen

Pretty big by embedded standards, that doesn't necessary affect the horse power required to drive it unless you want to pack every sq inch with dynamic information.

I'd be inclined to offload the UI to another processor. 4D Systems make displays with touch and onboard processors that will allow you to offload all the UI code from the main processor, they don't go to 9" though but there must be other brand around that do similar.

There needs to be 6 inputs for RTD Temp Sensors or Thermocouples.

TCs will need 6 amplifiers as it's not practical to MUX them AFAIK (there was a thread about this the other day).

All the other stuff would be OK I think. My gut feeling is that a Mega would handle this although I haven't put that much on one I admit.


Rob

Thanks for the suggestions. right now i'm looking at different avenues. I'm looking at using a tablet pc with a touch screen already.