According to the help topic "What topics can I ask about here?", it is not allowed to be "asking for a product, service or learning material recommendation". It seems like this is a general theme across all StackExchange sites. I have read some explanations on why this isn't allowed and I understand the reasoning, but there still seems to be a very real need that isn't being met and I'm not sure how it can get met.
Consider, for instance, that there is a certain specification of computer hardware that I have identified as solving a problem. I recall seeing this type of hardware at some point in the past, but all my searches turn up empty. Maybe the actual product is called something completely different that I wouldn't think to call it. Or maybe when I do find the product there are various examples but none of them are exactly what I am looking for and I wonder if I am missing something.
It would be nice to be able to tapped into the collective knowledge of others in a case where a search engine isn't suitable. In this case, I'm not looking to ask for a specific product to buy, although ultimately that may be what I want to do, but rather to find instances of a certain product which meet certain requirements, even though they may or may not be currently manufactured, as a baseline to determine whether or not what I am looking for is or has been out there. It could even be something as simple as somebody saying, "I have the knowledge of this sort of thing [expounding on that], and it has not been done [except for these related things which aren't quite what you are looking for]" which is not something that can be determined easily just through a review of what one can find.
Could such a question be on-topic here, and if not, what is a person expected to do who has already tried to do their homework (searches and whatnot) which have not turned up what they were looking for?
Or from a slightly different perspective, is it alright to ask for product recommendations from a historical perspective, i.e. has there ever been a product made that does "this"?