If you are referring to the red MacLean of Duart tartan as the "dress" tartan, then there really is no difference between the "red" and "burgundy" versions. I suspect what you are calling the burgundy is actually the MacLean of Duart tartan in the muted color scheme.

You might want to take a look at my article on tartan colors, which would explain why you see so many variations on tartans:
http://www.albanach.org/colors.html

As to where to buy a kilt in the MacLean of Duart tartan, any reputable kilt maker or Highland dress retailer can certainly supply that tartan, as it is woven by all the mills.

If you don't already have a supplier in mind, might I suggest ourselves:
http://www.scottishtartans.org

Click on the "giftshop" link to enter the shop.