Great question. I covered this topic recently in a podcast with Kevin Bupp and Charles Dehart. You can find it in the iTunes under "The Mobile Home Park Investing Podcast" Episode #26 covers appraisal related questions.
Most banks will not accept an appraisal done for another bank. While we as appraisers may be on the approved list for each of the banks you are shopping your loan to, it is not as simple as us just going back and changing the name to a new bank. Federal regulations (USPAP) require that doing an appraisal for a new lender is considered a new assignment, which will typically mean a new inspection as the "as is" date of value has now changed. This may sound extreme but it's how the rules are written.
I am an MAI designated appraiser through the Appraisal Institute. By the time an appraiser get's licensed and earns the MAI designation it's about a 6 to 10 year process. The designation is widely recognized by lenders, attorneys, accountants, etc., and in fact some lenders require it for certain projects.
Typically the bank won't order the appraisal until you have signed the loan commitment paperwork so in most cases you are already committed.