Please look at page 5 of this documnet:
http://www.ccm.udel.edu/STF/pubs_links/Wetzel-ARL_ASC_12-2-04_pres-pub.pdf
I would like to know where I can purchase the 450 nm colloidal silica.
As a $10 bonus I would also like to know where I can buy the Kevlar
also listed on this page.

Here is the article referenced in the article you had:
http://www.che.udel.edu/research_groups/wagner/website/awards_files/ADVANCED%20BODY%20ARMOR%20UTILIZING%20SHEAR%20THICKENING%20FLUIDS-Army%20conference%202002.pdf

They say they use Nissan Chemicals MP4540 (450-ish nm silica particles)

Snowtex.com (Nissan Chemical America Corporation)seems the most likely
supplier of this stuff, but the website doesn't list this substance.
You might have to e-mail them.

Easy to find in the PDF as well, but the Kevlar is Kevlar KM-2, 600
denier. First supplier on google appears to be
http://www.hexcelschwebel.com

The first part of the question is answered. The second part list the
correct manufacturer, but I was after a distributor who sells to the
public (not a wholesaler).  Thanks

I've found the folks at Bangs Labs, in Indiana to be extremely helpfull:

www.bangslabs.com

they have the following products:
Plain (Hydrophilic) Silica Microspheres
SiO2 with natural hydroxyl or silanol (Si-OH) surface groups- for
adsorption of nucleotides with low protein binding.

Catalog Code Diameter 
SS02N 0.00-0.49 µm 
SS03N 0.50-0.99 µm 
SS04N 1.00-2.49 µm 
SS05N 2.50-4.99 µm 
SS06N ?5.00 µm 


Prices are $84.00 for .5 g to $527 for 5 g

As you can see, its kind of a spendy proposition. You can make these
little guys yourself fairly easily via the Stober growth method, and
it would be a far sight cheaper, but harder to make sure of the
results.

Alternative suppliers would be
Angstrom Sphere
http://www.focenter.com/feature_angstromsphere.asp


Polysciences (another good company)
http://www.polysciences.com/shop/product.asp?dept_id=4060&pf_id=24323

nonoalchemist please post this answer and I will award payment. Please
give detail about the Stober method and I will award a total of $30.

Thanks,

Keith