If I am interested in an item described in a patent, how would I figure out t how to buy it / where to buy it? Even if I find it listed as a product, it often leads to a broken or expired link. Is there a general way to find out if an patented item is in production?
In general, no.
Also, remember that since owning a patent does not grant the right to make and sell the invention, but only to stop others from doing that, it may well be that an invention is patented, but that an earlier, broader patent prevents the patent owner from making and selling the invention.
That being said, a few jurisdictions require patent owners to, on a regular basis, submit "statements of working", which describe if and how the invention has been commercially exploited. (The goal of this requirement is to make it easier for local manufacturers to seek compulsory licenses - at least on paper.)
Update: actually, it seems that the database only covers the years 2012 and 2013 (!)
You can try to contact the owner of the patent (see How can I contact the owner of a patent?).
But in general, no, a patent can be traced back to the owner, but not to any product directly, so you can try to research that owner or the owners company maybe, other than that, there is no way to know from a patent view. Of course, you can try to find the invention via google.