That "Veggy's" place up near Sheraton Hotel has a few different brands of oats. They even have some organic oats in a bin towards the back of the store. If you're in that area, the Western market (Annam Gourmet) in Syrena tower has a few different kinds, too.

I've also seen a couple different brands at Western Canned Goods and Dan's, but I don't specifically remember "Dutch".

WCG is 2 mins from home, I'll check it tomorrow.

The only reason I remember Dutch is the cartoonish packaging with the lady in the funny hat. Like this:
http://images.buycostumes.com/mgen/merchandiser/2686.jpg

Funny that I can't find an image of it. Royal Lassie Mills Avena turns up nothing, unless my google skills have turned to suck.

I just got home from a mate's place who had it, he said he bought it on the Citimart on Cat Linh

They have it in L's Place on 34 Phan Boi Chau.