I've played around with my standard A3000D system yesterday and I've decided to see what it looks like when it is expanded with the following:
68-pin hard drive
CSMKIII accelerator
CVPPC graphics card
The end result looks really nasty. There is barely enough space available for everything to fit, but the real killer here is the SCSI terminators and cabling, and the "CVPPC to video connector cable". They clog up what ever little space is left over for air-flow. I always knew that this sort of thing wasn't really recommended even though both CSMKIII and CVPPC were designed to fit even inside the A3000D case, however I never imagined how tight this fit really was.
Although everything runs perfectly fine, I wouldn't dare leaving this thing on, running for longer than perhaps an hour...maybe less.
Some crafty modifications are definitely required in order to run this sort of setup with proper cooling, especially if you have a CSPPC, instead of CSMKIII which I used.
It would definitely help if I had a round SCSI cable that was the right size, but still...it's way too tight in there for comfort. :-)
I guess the first step to providing better cooling would be to cut a hole in the metal plate, and get rid of the right floppy drive mounting area, at least so that some of the cabling could be taken away from the motherboard and placed in the upper part of the case.
Just my 2 cents on the subject. :-)