quite a few sources when you google on "Bluebonnet seeds"

http://www.texasbluebonnetseeds.com/orderform.htm
http://www.americanmeadows.com/bulk_....cfm?itemid=99
http://www.flowersoul.com/flowerseeds.html.
http://www.wildseedfarms.com/texas_bluebonnet.html

best price seems to be wildseedfarms -- that's also where TXDOT
buys their seed from for the roadside displays. They're on 290
east of Fredericksburg.

Google is Great!
Hmmm wonder what the homeowner's association would say if I planted
wildflowers and did away with my lawn....? Then they wouldn't have to send
me anymore letters about how I need to EDGE my lawn.