If these apps are 100% java (no native arm code) as I think they are, then It might be possible to run them.
Another possible use for this would be to run apps and record the screen. Since this is x86 emulation, this should be much faster than the ARM simulator, so this would make really fluid screencasts.
(says the Android dev next to me)
Is this complete or perfect... perhaps not... but does it work... yes. Probably stamps over some license issues, you're not supposed to have the market on a non-grace of Google device.
I just didn't know if they'd run on an x86 processor, so this is good news.
The only hack needed for a decent experience is to either modify your system build.prop to make it look like a device that has real market support, or hack the Market.apk itself to make google's servers think your tablet is some device that it isn't.
If all you did was install the APK by itself, some Archos fan developer must have pre-hacked the market.apk in that way, but doing that is relatively easy and common and doesn't mean Archos had anything to do with it.