Agreed, towering will be a futile exercise in frustration. Best bet it to find a real Amiga case and be done with it. Failing that, you can just purchase an A2000 for cheap and keep your mobo as a spare.
And yes, a nice accelerator and a nice video card such as the one in my sig are the makes for a really fast A2000 system. Zorro II and all. Having a little experience with MorphOS on an Efika, I can tell you my A2500 setup BLEW it away as far as the Desktop graphics speed and overall snappiness of the system in general. Slight apples to oranges comparison there (as far as the functionality of some of the programs), but I wouldn't be discouraged from exploring and upgrading your A2000...