Presenting the case for good online form design.

Hi all,

I'm in search of some statistics and advice for a meeting I have on
Monday. My situation is that we've designed and are nearing
completion of developing an online membership activation form. It has
a reasonably complex set of business rules which must by met and an
offline activation form will also be made available, although one of
the project objectives is to streamline the activation process. In
this, the 11th hour, we've received a new requirement to include a
new set of 'terms and conditions' the user must agree to in order
to complete the process. That may not seem so bad, but it will make
the 3rd such agreement the user must make in a 7 step (including
landing and success pages) form - the other 2 are Terms and
Conditions of Use and a Privacy Policy (has anyone else even heard of
something like this?). They are all being implemented half-screen
scrolling divs of content with a checkbox to indicate agreement. The
checkbox label is 4.5 lines of legal jargon :( Anyway, I have a
meeting on Monday to raise my concerns about the impact the addition
of this 3rd required agreement will have on the usability of the
online form - namely that it will cause confusion and scare people
off. I'll be facing the legal rep. who is driving the inclusion and
three stakeholders who are very focused on the deadline. Any of the
following would be very much appreciated:
# hard stats and real world examples of IxD/usability's impact on
online form dropout rates (theory and best practice I already have a
lot of)
# information regarding the legality of different types of online
agreement interfaces - i.e. is a link to T&C sufficient or must they
be displayed on the same page, checkboxes vs. 'I agree' buttons,
etc.
# any advice or experience on dealing with this situation

Thank you. Wish me luck.

Marcus