I was wondering if the sugar in skim milk could make a good post workout carb source if mixed with whey protein. All opinions are appreciated and welcome.

What would you recommend? Waxy Maize starch?

I mix my whey with skim milk everyday for post workout or with 1% chocolate milk

Lactose is a form of sugar. It is a very slow digesting sugar so as far as energy goes it acts like a carb. It is not a carbohydrate though and will not be quite as useful to your muscles as a real complex carbohydrate. Waxy maize works very well too. That said I love milk as a protein source. Combined with the whey it should do you good, but I would add some sort of carbohydrates in there somewhere.

Milk digests much more slowly than whey, so ideally you don't want to mix your whey in w/ milk and slow it down. Post workout you want an immediate source of protein (whey) and a fast source of carbs.

WMS is a great source of quickly absorbed carbs. When I use it, I'll down a couple scoops and then wait 20 mins til it clears the stomach and then do my whey. of course you can always drink gatorade and then whey a couple mins after that, too. Sometimes I'll even drink a soft drink to get my post workout sugars.