Hi Lee,
I would suggest that your best bet would be to contact a few potential providers and be honest about your concerns. Most half decent providers would bend over backwards to provide you with case studies and business case assistance if it means the increased possibility of sealing a deal with you. After all, all of their clients will have had to go through the same thing you are, so they will surely have someone that can help you or put you in contact with one of their existing clients who can.
Good luck with it anyway and let us know how you get on - Web chat is something on my ever growing 'to do' list too so would love to hear how it all turns out for you.
Regards,
Matt