|>>|| No. 10495
No. White chocolate is make with cocoa butter only, in comparison to dark chocolate which is made of both cocoa butter and pure cocoa. Milk chocolate is simply dark chocolate with added milk.
In addition to this, dark and white chocolates have different melting properties, meaning it's quite difficult to get them to mix. Even if you did, what you'd end up with would taste more like incredibly sweet and fatty dark chocolate than anything else. It wouldn't be very nice, and wouldn't taste at all like milk chocolate.