Heh, I see a LOT of Android 2.2/2.1 and even a few 1.6 devices on that page. Most of the ones claiming 4.0, if you look closely at the pictures, it's not the 4.0 interface (some of them have the old search bar from the 1.6 days). I don't know if the pictures are just wrong, but I certainly wouldn't trust them with my money.
The few that did claim 4.0 and did have accurate pictures, the specs were pretty poor and the price wasn't that low.
dealextreme really aren't at the cutting edge of things in this market. They are trading on the fact that they have 'brand-awareness' and trust and that people assume they are the cheapest. Reality is they have a bunch of out of date stock that people in china wouldn't buy.
If you want to explore this wonderful world, i'd look at the manufacturers first. Ainol (worst name ever) are the dominant force in the market IMO. The novo-7 fire is basically a nexus 7 with a microSD slot, for (in the west) ~60% of the price.
The few that did claim 4.0 and did have accurate pictures, the specs were pretty poor and the price wasn't that low.