If I had an infinitely large paper, how could I draw an n-element karnaugh map for (n>6)?
DRAWING a large Karnaugh map is simple. Let's say you have an n-bit system where n is even. Then you simply make a square K-map, with M entries on each side, where $$M = 2^{\left(\frac{n}{2}\right)} $$ So, for instance, a 20-bit system would need a map with \$2^{10}\$, or 1024 entries on a side, for a total of 1,048,576 cells.

The problem is not drawing large K-maps, it's using them.