Input device stacker?
 

I've found an output and a DSP stacker, is there an input device stacker?

Input Device stacker? What do you mean exactly?

All input plugins (in_*.dll) are loaded at Winamp startup, and are all permanently active.

not even sure why you'd want to stack input plugins since they are generally used as per the filetype/playlist entry which it detects as being it's to play. and like Egg says, they're all loaded whilst winamp is in use. the most you can do is have a input plugin wrapper (like my in_zip project which will just feed extracted files to the already loaded input plugins). and like Egg asks, why (since i'm baffled, heh)

-daz