I had some initial success with putting Android 2.1 from JetPlatform-experimental-binary-100624-2.6.29.tar.gz or JetPlatform-0.3pre1-binary.tgz while retaining the original linux kernel 2.29 on the inbuilt 1GB card. To do that I had to open the device.
Some things were not working 100% correctly with the new android so I put back the original card. 2.1 was faster than the 1.6, but home screen was blinking from time to time.
Also my chinavasion model did not had volume buttons, so I added them from an old Lexmark printer, pictures here: slatedroid . com/index.php?topic=7344.0 (scroll to page 15).
PS>Did you notice some software upgrades on this page: download . chinavasion . com ?,
look for device code PC07, some users said the wifi update is helpful.