Is there a graphical pager?

You can pipe into leafpad. I don't know if there's a Mac port though.

Kate

You can pipe into kate, using command | kate -i.

From $ man kate:

   -i, --stdin
       Read the contents of stdin

Kwrite

You can pipe into kwrite with command | kwrite -i.

From $ kwrite --help:

-i, --stdin                Read the contents of stdin.

Gvim

Somewhat facetiously, you can also pipe into gvim with command | gvim -.