I use Activestate's Komodo IDE. It has good SVN integration and can open files from remote servers (including FTP). With a very large project it can get a little slow/clunky but it's general pretty fast.
Komodo IDE is a commerical product (~$300 USD), but ActiveState have a cut down open source version called Komodo Edit but I do not believe it has SVN support.
An alternative for FTP support is to use a a program like Fuse (OSX/Linux only) to mount a FTP server as a directory, I believe there are a couple of commercial Windows programs that offer similar features.
