As a multi Dell frankenstein PC owner. I will say under some instances I have been able to place dell boards in standard PC cases. I will say you will have to remove the mount that holds the system board to the PC from the case. In the older GX1-110-170's you would need to pop the rivits that heald it to the case. If your unsure what this is.. It's the little hooks that hold the board in place and is also the ground source for the board. On the newer gx200 and higher boxes this tray now comes out as a whole and can be placed in a box rather easy.
As for the home series PC's I'm not that firm on what they can and cant fit in but I can asure you each model has it's quirks and kinks. Some will need the dell power supply and some can use standard ones. Some will need the power button panel and some will not

you get the point.
Hope it works out !