Although it's not a novel, a currently running comic book miniseries that might be of interest is "Star Trek/Legion Of Super-Heroes," published by IDW and DC Comics. It features the:
- The classic Star Trek characters (as they were in The Original Series).
- Members of The Legion of Super-Heroes, a team of superheroes from the 31st Century who work together to protect the United Planets (they appear to be from the original Legion continuity).
Due to a temporal disruption, both teams end up in the 25th Century...but a very wrong 25th Century.