If you've been to Hanoi to HCMC, it would not be hard to spot Apple shops along main shopping streets (there must be a demand for such shops, right?). I agree that Apple laptop is more expensive but to the middle class in big city that would not be a big deal. The main issue with Vietnam market is that people still associate computer in general with Windows, thus they don't want to make the switch. The first reaction I got from my friends 5 years ago when they knew I was using a mac was "Does it have microsoft office?".
Regarding the iPhone, Vietnamese are crazy for the iPhone 4. Rich kids want cool looking stuff, they don't care about the price.
Btw, Apple even have an online store for Vietnam: http://store.apple.com/vn