Well there you go, I've finally found the answer, and here on this forum... just needed to use the right words to search for.
So, I googled "disassembling an archos 70 internet tablet" which pointed me to a thread on this forum...http://forum.archosfans.com/viewtopic.php?f=73&t=43017
...which pointed me to this disassembly in pictures page...http://bbs.imp3.net/thread-953667-1-1.html
...and ultimately this image...http://reviews.imp3.net/archos/archos%2070/c/13.jpg
...and after all that the Archos 70IT 8GB Battery Capacity is ... 3850mAh