Hello Jen/Stumpy.
Jen, I never heard of The Machine Shed but it sounds like they sell the same type of dishes that The Cracker Barrel (another chain) does. Cracker Barrel's food is home or farm style cooking. Their Chicken Fried steaks are good but, I found a local place whos CFS is better than theirs is. They have a great Meatloaf dinner, as well as their Chicken and Dumplings dinner. Those are all I have tried in eating there for over 10 years now. One item that they have never been bested on is their Sweetened Iced Tea. I absolutely love their iced tea. Oh I almost forgot that their Biscuits are to die for--especially if you put strawberry or grape jelly on them that is from Knott's Berry Farm. Now I wished that I had not had a Cheeseburger for lunch before coming here. 
We also had a new restaurant open recently which is called: Fuddruckers. I ate there once in San Antonio and loved it. I will definitely give The Machine Shed a try if they ever venture down this way. I'm always open to a new taste in the thinks I regularly eat.
Stumpy, next time I am in San Antonio, I will give the Jailhouse Cafe a try. It sounds like a Mom n Pop type of place and I love those kind of places. The Sheriff's Special sounds like the normal CFS you get at The Red Barn. I don't recall if Red Barn gives you a choice on size of steak or not but, like Jailhouse Cafe--you better come famished or you aint going to finish that meal. Last time I was there (a few years ago now) for about $5-$6 bucks, you got a CFS that over-lapped the edges of the plate, French Fries that covered about 1/2 the CFS, a huge roll, a salad and the standard glass of tea (or whatever you wanted to drink) was in a 50 oz ++ glass. Even in my best eating days, I could pack away the CFS, the roll and some of the fries and salad, but not these days.
I do love Mexican food and will try La Posada Del Rey when next in Rome as well. We have nothing to compare with San Antonio in the way of great Mexican food. We also do not have a single German establishment either. I have been to The Barn Door, and remember it was a pretty good place. We ate there after my Uncles Funeral back in 2001. I think I had a London Broil kind of steak--which was great.
Oh and if you ever have the chance--eat at a great place called: In Old San Francisco. This place is a bit expensive but, it's also because you get live entertainment in the way of Magic, Piano, and Acrobats. Finally in San Antonio, you have to try The Magic Hour Glass.
If ever it Houston, you MUST try Dirty's. It's like the Red Barn in the size of servings, price and such but, you also get to put some graffiti on the walls and table (which is tradition there) Another great place in Houston is, The Mason Jar. A bit expensive but is great as well.
Last but not least, you MUST try Mamacita's in Houston for great Mexican food.
If ever down Corpus Christi way, must tries are: U & I restaurant, Longhorn Steak and Ale, Bennigan's, Outback Steakhouse, The Cracker Barrel (of course) and Walbangers (which serves other things like steaks and such but is more famous for their stuffed Burgers.
