Never have I seen a mobo to allow changing the of the logo, and I have been in a lot of mobos (I build and salvage computers as a hobby, and IT as career).
I have seen a few that allows turning off the logo.
there should be other options where you can have it set to show POST progress (or detailed startup) where it wont show any logos.
I always like it to show POST rather than just a logo, bec I like seeing what it is doing.
Plus showing post is similar to watching mame games go through its startup sequence, so in a way, showing POST kinda fits for a MAME PC IMO.