AAttention Bakers! I would like to bake a 10 inch cake but I want it to sit about 12inches high including filling. How do I do this???

Have you stacked a normal tiered cake before?  If so, then kind of like that.  I would do it in three sections of 4" high, with a board and dowels between each section, then crumbcoat and ice all together.  It's just the same except you do the dowel-and-board-ing before the icing, rather than after.

Hope that is clear enough!