I have built a decidedly plain looking Lego case, but I thought I'd share the way I've mounted the PCB; it's not necessarily better... just different!
The bits I'm using are a Angle Plate 1X2/1X4 and a Plate 1X2 With Slide:
These are assembled like this pictures to provide the "rail" for the Raspi's PCB:
This is where I positioned each of the rails relative to the PCB. The one near the ethernet port is quite far forward because the one of the soldered connectors seemed to hang down quite low there:
The one behind that was is beside the power thingamajig (stop me if I'm being too technical!). It's not closer to the power connector because there was a component of some kind on the underside of the board that might get in the way:
The one near the GPIO connector is right on the corner:
And on the final corner, it's positioned beside the indicator lights.
The "Pro" for mounting the PCB this way is that it can't move up/down when moving the case about, and obviously the walls prevent it moving much in any other direction. However, the "Con" with this arrangement is that it's harder to build. You can't slide the PCB into it as the various connectors get in the way, so you pretty much need to build the "case" around the Raspi.
*before anyone mentions it, nope, I'm not using my HDMI or my audio connectors!
