SVN client on windows without administrator rights
Ok, I finally found out the (I think) correct answer to this question. The zipped binaries are available in the win32svn project here: http://sourceforge.net/projects/win32svn/files/.
In the subdirectory of your favorite version, just download the file that has a name like svn-win32-1.6.16.zip and unpack to your home dir, local hd or (in my case) usb stick.
Hope this helps someone! I was very surprised to find all links I found pointed to installers which you may not be able to run when you don't have adminstrator rights.
EDIT: this is, of course, the CLI version; I guess this answer is more for people who, like me, are looking for it and arrived at this question :)
This is a late answer, hope it help someone else. My answer is smartsvn, it is a perfect software, with foundation version free to use.
In their download all page, you can download a portable version, jre is also included in this zip package, that means you can even run the software without java installed, since java is not included by default in the latest windows system.