I can't speak for JGroups (definitely going to check that out tonight), but spread and Vsync/ISIS both struck me as perfect examples of the meme of poor quality academic code.

Spread is an #ifdef soup containing scary stuff like "#ifndef _REENTRANT" in their hello world examples. Additionally it has a weird not quite BSD licence that doesn't look compatible with the GPL. It also makes you send them either an ssh key to checkout from subversion, or send them email/name/company info just to get the download link working.

Vsync/ISIS is a single 50KLOC C# file that spawns upwards of a dozen threads on init.

IMHO there's room for someone with more of a software engineering background to come in and clean them up (assuming that this person/group knows enough about distributed systems to clear things up without introducing more problems).