pro bikes and professionals

I think it happens more with components these days.

Certainly in the spring classics I recall seeing some mentions of wheels and groupsets being rebadged or blacked out for various reasons.

Until recently a lot of Pro teams still used custom frames built by independents, particularly in TT's. I cant remember any examples but it used to be pretty obvious, as the bikes typically looked nothing like the TT offerings by that manufacturer (if they even did one). Today i dont think it happens as much, youll still get riders on custom frames (ie. stiffer, custom sized or lighter) but typically they come from the R&D dept of their sponsor. Most of the bike companies involved in sponsoring teams these days tend to be pretty solid with a good model base to choose from.

I don't think this happens on pro bike frames. There are enough differences between carbon frames for them to be easily identifiable. There's quite a lot of re-badging of consumer frames though, such as Dedacciai / Ribble. And a lot of different designs may come out of the same few factories in the far east.