Exclusive Locking

Hello,

My company's evaluation of Subversion is being shot down because of the lack of
an exclusive locking feature in the current release -- some developers are just
uncomfortable with merging(!?).

I was wondering if the members of this mailing list could help me determine
under what time frame and at what cost we could get exclusive locking into a
stable Subversion release.

I would like to be able to bring approximate answers to the following questions
back to my company's "decision makers."

1. How long does it take a competent coder to understand the Subversion code
   base enough to be able to contribute a significant patch?

2. How many programmer/hours of work would be required to get exlusive lock
   support into the stable version of Subversion?

3. Are the Subversion project leaders in a position to negotiate for
   sponsorship of this feature?

4. Are any Subversion contributers in a position to consult for this kind
   of work?

I'm sure everyone is aware of the substantial licensing costs of Subversion's
commercial competition; I wonder if either a direct financial contribution,
or a contribution of time of an in-house developer or third party contractor to
the Subversion project would be competitive with those costs?

Thanks,
  Seth de l'Isle