Paper

what size?

8.5 x 11?

how about simply using the A series, which have a $$1 / \sqrt{2}$$ ratio this'll allow the printer to adapt easily to multple sizes (A4 portrait == A5 landscape just with half the height.)

Advantages

 * Can take thicker card stock
 * Easier to manufacture printer

Disadvantages

 * Increased risk of pulling through multiple pages at once

Advantages

 * more consistant paper pull through

Disadvantages

 * thicker card stock gets caught easier
 * slightly more difficult to manufacture curve to bring paper around

please add to this list as desired