There are a few places on the internet to find postings of Jaime Hernandez original art and the many, many convention sketches and commissions he's done. Flickr is a great place to find higher quality posts, and I'll be looking there in the future. Today here are a couple major websites and a couple more suprises I found using a different search engine over the weekend (yahoo, I think):
The clearinghouse for alternative cartoonist commissions and illustration work seems to be Comic Art Collective. All of Jaime's entries are sold, but I believe you can still take a look at all the dozens of rare illustrations you wouln't normally come across.
Comic Art Fans is a nicely put together website, with 162 of Jaime's sketches (some original art, too) posted from 1/7/2004 to 10/27/2009. Interesting sidebar on this site is "Market Sales Data for Jaime Hernandez" which lists original art pages, the prices they have sold for, and even the date they sold. Yeah, I'm not affording any of those anytime soon!
Check out this page for two pieces of exceptional original art, including the splash page of Jaime's "Ninety-three Million Miles..." story and the cover to TRANSMETROPOLITAN 32.
Here is another great example of Jaime's fabulous femmes posted by the owner of the illustration back in 2004.