Exact-o-mundo ... you can make a grouping of Mac Minis for CGI rendering, lashing them together and co-processing the edits, etc. (Check out the Maya demos = academy award winning stuff).
If you are doing mainstream theatrical movies, with or without CGI animation, FX, etc., and want input from high resolution HD-SDI type cameras (and other sources), you might consider getting a full sized Mac Pro as the central workstation. That way you can add the plug-in cards to Input/Output the ~3 GigaHertz HD-SDI (1080P & DisplayPort quality) camera signals for processing. (IMOP: HD-SDI/DisplayPort is the target technology for the next generation of professional video production, whether garage band demos or mainstream movies and TV. Anything less is YouTube quality =
... anything more and you need help from George Lucas or JPL/NASA )As with professional audio, you need to start with master source recordings of as high a quality possible. The HD-SDI device scenarios are about as high-rez as can be had and can be used as source masters for mainstream theatrical movies. A bit more budget minded approach might be to hold the line at 1080i, which is plenty good enough for broadcast & cable TV quality ... and could be edited, massaged and rendered with a couple or three Mac Minis = no problem-o.
A small cluster of Mac Minis, lashed together for co-storage and co-processing power via FireWire 800, can do wonders for movie and video productivity. The CGI rendering software is the key and the Mac OS can do ...
The best advise is of course: don't start buying equipment until the script is budget approved ... and the check clears the bank
So, Can it be done? = Yes. >>> Should it be done? = Is your target audience sufficiently large to justify the extra work and cost$ ... $$$?