Making re-search-backwards greedy

[Eric Abrahamsen]

I seem to remember there are Hard Problems related to reverse regexp
searching, but I'm hoping this isn't one of them.

Here's my situation:

(let ((regexp "\\(bo\\)\\{2,3\\}"))
  (with-temp-buffer
    (insert "bobobo")
    (re-search-backward regexp)
    (match-string 0)))

The problem is that this returns "bobo" and not "bobobo". I'd like it to
go for the longest string possible. Is that feasible?

Thanks,
Eric