Any auto paint supplier will have the sand paper.
NAPA Has It. ...bottom of the page.
Micro Fine 1200, 1500, 2000 grit wet/dry, but it doesn't show how many sheets in a $6.49 pack. I'm sure you can find a body shop that will sell you sheets at cost/cheap.
I'm kinda interested in doing this myself, but I abruptly became unemployed last week. lol
Figures, all the time in the world to tackle a project...but I don't have the money to spend on it