DIY Ribbon Mics

http://make_a_ribbon_mic.tripod.com/id3.html
http://www.diyaudiocomponents.com/ribboninfo.php?sub=5

Magnets:
First 4 Magnets 
http://e-magnetsuk.com/magnet_products/neodymium_magnets/rectangular_magnets.aspx (N45 magnet, similar proportion)
http://www.kjmagnetics.com/products.asp?cat=11  (4in long magnets is interesting)
http://powermagnetstore.com/acatalog/index.html

Foils:
http://www.lebowcompany.com/foils_list.htm
http://www.advent-rm.com

Fixing Ribbons:
http://www.lkmusic.co.nz/ribbonfix.htm
http://www.hometracked.com/2007/08/28/ribbon-mic-sag-and-repair/

DIY Preamps:
http://sound.westhost.com/p-list.htm

CAD related stuff:
http://www.eland.org.uk/pages/Misc/cadnotes.html
http://www.punchcad.com/p-9-viacad-2d3d-v8.aspx

Uh... too advanced stuff.
http://www2.hud.ac.uk/ce/research/conference/presentations/Presentations-4-M-J-K-Aitchison.pdf
http://downloads.bbc.co.uk/rd/pubs/archive/pdffiles/monographs/bbc_monograph_04.pdf