I was thinking of getting a machine shop to reproduce patch pieces for those hard to get at areas. You know those corners in the front and rear windshield areas that rot out, and in the trunk area where water gets trapped under the weather stripping. If there was enough demand, I could probably get the work done at a price everyone would like. It sure beats the heck out of fabbing thos corners by hand. I know I am not that great with a stretcher/shrinker. What do you all think?

What you're proposing is not a job for a machine shop but a sheet metal fabricator. I do this for a living but in our business we do what's called "soft tooling". We have turret punch presses into which we load up to 58 tools of various shapes (rounds, rectangles, squares, etc.) and punch out our parts. We then send them to the bending department where they are formed on press brakes. The big limitation here is that you cannot really have any compound curves in this type of process. Since the patch panels for our cars typically have compound curves or return flanges along a curved surface, they must be stamped in a press using a dedicated (and very expensive!) die. This is referred to as "hard tooling".
What we do as hobbyists using hammers, dollys, stretchers, panel bags, etc. falls under the umbrella of another type of "fabrication". It's fabrication in its purest form and is the only thing the average Joe can do to replicate the results achieved by the vehicle mfr. with hard tooling.
I'm sorry for being so wordy, and hope I've answered your question. Not trying to plug our company, but if you're interested in seeing a little more about this process our website is www.evsmetal.com
Tom

Do you mean just the corners in those spots?

Full and half patch for trunk gutter, window channel up front, etc already out there and available.

My metal fab sucks so my fix is to by those pieces and cut out what I need for the patch. Cost a few bucks more but well worth time and aggravation saved by me attempting to make a patch.

Not sure if you mean just those tiny spots like the actual corner and a patch that would be, say, 3 inches in length, ready to go and shipped.

Seems like they repop every panel nowdays. Always will have some fitment issues no matter where it comes from but I think just about everything is out there now

Having said that - I could use ALL the patch help I can get and if there is more available and makes life easier, keeps me from hacking at a full or half piece to get a tiny patch then man im all for that...

If the OP is actually referring to machining this shape, he could be on to something. I would yield a very tight tolerance part a would repeatable in a consistent fashion. Downside would be high cost -- but maybe not that high compared to limited run sheet metal stampings on dies of limited quality.

Thanks for the feedback guys. I guess it wasn't such a good idea :)