I vote for PVC. Circular base with a center mounting slot, all sanded with 80 grit and painted green glass or matte, your choice.

Or....

Find a broken or cheap fan with stand (Craig's List) and just recycle the bottom end, painted green or whatever.

http://www.google.com/imgres?imgurl=http://www.comparestoreprices.co.uk/images/bi/bionaire-stand-fan.jpg&imgrefurl=http://www.comparestoreprices.co.uk/compare-prices/bionair&usg=__qbziLcryilzI3JidusSx8J1jFB0=&h=298&w=298&sz=11&hl=en&start=0&zoom=1&tbnid=KEiSm6u3RotW7M:&tbnh=136&tbnw=136&prev=/images%3Fq%3Dfan%2Bstand%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-USfficial%26biw%3D1680%26bih%3D858%26tbs%3Disch:10%2C70&um=1&itbs=1&iact=hc&vpx=1308&vpy=542&dur=50&hovh=225&hovw=225&tx=136&ty=185&ei=4kv9TNGQLMGB8gaf3u3lCg&oei=4kv9TNGQLMGB8gaf3u3lCg&esq=1&page=1&ndsp=40&ved=1t:429,r:38,s:0&biw=1680&bih=858

__________________
2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)