Sorry raschemmel for being a bit vague in the first place. I'm probably a bit unorganised when it comes to to circuit design. I tend to draw in block form until a design intention is formulated so being asked for a schematic at this stage threw me a bit!. All I really know is that I will be using an LM35 for temperature sensing and n-channel FETs on the PWM outputs, mainly because I don't know exactly how much of what spec LED I will be using. I hate Fritzing myself but thought it would do to give you an idea of what my intensions were and I failed 
In reality, what is stuck on the PWM outputs is a bit irrelevant at the moment, so long as I can get a sketch to do what I want it to do.
I'm a lighting designer by trade and I thought that the arduino would be perfect for this little side project since DMX, DALI, etc would be a bit of overkill for what is in essence a one-trick-pony!
So, shall I come back when I've spec'd up all the hardware?