It looks like ebay is putting up some verification codes on myibidder. any chance that you can introduce a button on each listing (something like bid now), which will try to bid, see that there is a captcha and present the verification back to user - this way if user get this through ibidder they will be able to verify an account and hopefully mark your IP address as valid?
If you can bid when you click the button, it does not mean it will be the same next day when auction is finishing.
The last issue seems to be resolved as it works fine as of now.
Sorry for any lost snipes.