Doyle,take a look at these sites;
www.geocities.com/hardeeflag/prentice/prentice.htm
www.nsalliance.org/uniforms/texaslouisiana/jackets.pdf
This is the only example of a summer jacket that I know of. However, if memory serves me right, I seem to recall Tom Ezell mentioning clothing made from onasburg at the Huntsville prison in Texas. Contact Tom, as you are quite aware of how good my memory is.
Chuck