Here is a list of tools that you will need to create an SVCD on your Mac.
DVDExtractor (Classic app)- Rips and demuxes tracks from a DVD into audio and video streams that you must decode.
GNU vcdtoolsX - A GUI for a collection of UNIX commandline tools for imaging a (S)VCD.
mAC3Dec (Classic app)- Decodes the AC3 audio track created by DVDExtractor into AIFF audio.
MacMPEG2Decoder - Decodes the video track that DVDExtractor creates into a suitable format.
M.Pack (classic app)- Encodes the Quicktime movie into an SVCD compatible MPEG stream.
Quicktime 5 Pro Key - This unlocks all the Pro features of Quicktime such as saving and editing.
Toast 5 Titanium - This is the program I use to burn CDs, although any program that can burn Multitrack CD-ROM XA will work.