I used
Cellarack – The Wine Rack Shop – Custom Wine Racks in Melbourne (I'm in Perth) to provide racking, insulation and cooling system to turn a small existing storeroom into my cellar. I was extremely happy with the level of service and product received.
I just see now on their website that they've had a bit of a disaster and change of ownership though. Still might be worth getting in touch.
Just looking at your floor plan, the space allocated to racking looks quite small. Keep in mind that if you plan on putting a cooling unit in then you will lose some more racking space on one of the exterior walls. If its a box type unit, you'll loose a lot. If split, then probably not much. I didn't want to lose space at all so went with the Fondis door cooling unit. You could do the same, but might be less suitable for you given the high visibility of he location. also the door would open outwards.
If you wan more details of what I did or have questions, just ask
Edit: I have to say that the convenience of a cellar over a fridge is huge. I previously had one of those large Liebherr fridges filled to the max. Great unit, but playing tetris did get annoying sometimes.