* android uses git (under the hood). I don't see a problem with 'large'
trees. Maybe it isn't large enough for you. Seems to work for many.
* git-svn taking time is SVN's fault, not git. git svn is a bridge that
will check out the revisions using the svn client, one by one. As said
later in the comments, keep the git-svn clone on the server, done once
people will clone from that one instead.
* from my experience a full git history takes less space than the latest
svn checkout. And you can fully work offline, do branches, etc.
To me, SVN is an outdated technology. Git is harder to learn though and
people can (& do) make mistakes until they grasp properly the DVCS
Note: hg is a compelling alternative and some people might want to look at http://hginit.com/ for introduction