Where to get unbiased outside counsel?

I am responsible for our current production computing machines, and it has become apparent that we will need to change system platforms and partake a massive application development effort to change our primary application to another application environment. A HUGE undertaking.
To date, I know of no consulting firm that is unbiased. (I consider Gartner group extremely biased – a valuable asset, but extremely biased)
Have any of you found any vendors that are in general unbiased, that haveexperience with multiple operating systems, including OpenVMS and manufacturing production environments?

Thanks so much !!

Rick