Proclaiming any product to be an "iPad killer" is a lot like the boy who cried wolf: Lots of noise and scurrying about, but ultimately no devouring takes place.

We've seen initial Galaxy Tab numbers proved flawed. Motorola Mobility's (NYSE: MMI) Xoom hasn't lived up to the buzz as the first gadget built on Google's (Nasdaq: GOOG) tablet-friendly Android 3.0 Honeycomb. Research In Motion's (Nasdaq: RIMM) PlayBook stumbled out of the gate.

Game over, Apple (Nasdaq: AAPL) wins?

Not so fast.

One of the worst kept secrets is that Amazon.com (Nasdaq: AMZN) is working on a tablet. "Stay tuned," CEO Jeff Bezos teased when asked about it in an interview last week.

It gets better. A tipster is telling connected tech blog BGR.com that Amazon will be coming at Apple from both ends, rolling out both entry-level and a high-end options later this year. Both tablets will be powered by NVIDIA (Nasdaq: NVDA) chips, though the pricier model will be a quad-core processor beast.

Why should Apple worry about Amazon if it has already vanquished seasoned hardware, smartphone, and software giants?

Well, what makes an iPad special? Steve Jobs doesn't sprinkle pixie dust on every tablet. Consumers flock to the iPad because it has the rich apps ecosystem and easy access to multimedia.

Amazon is no slouch. Kindle is the top dog in digital books. Amazon sells digital music, movies, and games. Some of its more recent moves also make a lot more sense with an Amazon-branded tablet in the bigger picture. The cloud-based music service and the growing digital video library available to Prime members at no additional costs find Amazon actually ahead of Apple in features that will add material value to a stand-alone tablet.

Apple may be selling more than a million iPads a month, but it can't get too cocky. Things are about to get interesting in the tablet market. For once, reality's aftertaste may be tastier than the pre-release hype.

Can Amazon really take on Apple in tablets after so many giants have faltered? Share your thoughts in the comment box below.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.