Well, I imagine one way you can confirm whether or not it has to do with architecture is to download the 32-bit package from the official site, then replace the one that SpeedofMac's GUI contains.
As far as 64-bit goes, I finally figured out what was preventing me from compiling the Z64 video plugin. Once I fixed that it built fine, but I couldn't get video to appear using the official RSP-HLE plugin. I guess because Z64 is low-level and must be used with its own low-level RSP-Z64 counterpart. I made it so if you run the Z64 script, it will always choose the RSP and video plugins together.
Anyway, I made a new bundle with it, and likewise a new disk image. Here you go:
As far as I know, there aren't any other official or 3rd-party plugins (at the moment, at least). That makes this the most complete bundle available.