Let's just wrap up some history
This going to take a tad longer, but there is a reason for this.
Anyone old enough to remember the eighties, when suddenly a new device made it into the households? The 'white box'es? White, why? Because for some reason, IBM had decided to build a computer of small size and tiny performance essentially from - already then - off-the-shelf parts. Microsoft was given the task to write something that allowed a user to handle this crude family of advanced calculators. Since the assembly of the off-the-shelf parts was essentially unencumbered by patents or copyrights, any - and that was the start of computer industries in Taiwan - company had the legal right to assemble similar boxes. Suddenly the PC was born. And nobody expected to have those boxen running any of the existent operating systems, nor software (Unix, RSX, VMS), neither applications. They would not natively connect to teletypes, VT100 terminals, Token-Ring.
Twenty years further, Asus blew a similar opportunity: The original EeePC. That was a ground-breaking, essentially new setup: all benchmarks, power, speed, mega- and gigabytes had been disregarded, and a box created that would just basically connect to a network and allow the user to do his daily browsing and e-mailing (and a bit of basic text editing) work on an astonishingly small and light and cheap box. Acer jumped in, with the famous Aspire One, here to be noted mostly: the L110, based on a flash drive, of 8 GB, no rotating platters. Both blew it together. Steve Jobs would have created the demand for that type of machines, but Asus and Acer modded their own boxen down to a low-cost PC; without full functionality. And everyone who fell for it, tried Windows, Microsoft Office, found insufficient space just for the basic install. And Crysis would not even start loading.
No wonder, that the 'white' PCs were huge successes; while the netbooks failed.
Back to the present. IPad is a successful product. Despite it not running actually anything. Not even OSX. All apps come from some proprietary store. But almost everyone is happy. Despite of the castrated nature of the device.
IMHO, the success of an iPad-killer does not do much depend on the power, speed, RAM, blabla; than on the type of product as which it will be sold. An iPad imitation? A revolutionary productive tablet? A PC with touch screen (only)?
It looks as if someone who re-creates something like the 'white' PCs has the best chances: Make it a revolutionary new hardware. A hardware doing what the user / owner wants it to do. E-book reader? Fine.Running Debian? Fine. Let the user decide what (s)he wants to do with it. Ubuntu Maverick must support it. Sell it with a profit, and allow everyone to put onto it what they like. Video-editing? Go ahead! An unconventional W7 machine? Install it! Make it open in so far as everyone can customise it to what he/she wants it to be. And not only the wallpaper.
The success of any of those 'killers' will depend on this. NOT to be a 'second class' member of the iPad family; a pale copy of a successful product. But, a new, revolutionary, tablet without keyboard. To do with it, whatever you want to do with it. It is yours. Take possession of it. It will do what you want it to do. Not like the applish 'we-know-best-what-is-good-for-you'.
Most of all: make it a NEW product. Invite world and dog to use it.