There a couple of places between Fredericksberg and Johnson City that make their own peach ice cream when the peaches get ripe. They sell all things peach -- preserves, pies, ice cream, etc. I can't remember the names of either of them, but if you are in the area, just drive from one of those towns to the other and you will find them.
Blue Bell's Peaches and Homemade Vanilla is a year round flavor; in season, they have Peaches 'n Cream or Peach Cobbler, I think.
In Houston, Hank's Ice Cream -I'm sure they'll have a peach, if not year round then seasonal.
In Austin, San Antonio and Houston, Amy's has several Peach ice creams listed.
I've had BB, years ago, never had the Hank's or Amy's.
Not sure your reason or motivation for asking, so don't know if this will be of help, but when the Texas Hill Country peaches are in season, there are several fairs and festivals in the region, many of which feature peach ice cream made by orchard owners, proprietors of local fruit markets and stands, etc.
It's a great time to visit the Hill Country. And that peach ice cream is to die for.
You can google the various towns and counties to see when each will be holding their 2011 peach festival.