What do you think about single product sites? Is this business still profitable? Do people still buyes from this kind of websites that sells some old software or book that you probably fiind it free if you search for it ?
A single product sites can be profitable depends on the product you launch but it does not make sense if you would like to sell stuff which are freely available.
Single product sites can be very profitable - if you choose the right product... Also, it is easier for single product sites to rank high in the search engines... Depending on the product niche you choose, create content relevant to that product (articles, tools, etc.) and you'll see traffic increase to your website..
A single product site has many advantages SEO wise, it will be easier to rank organically for your target keywords with an entire site devoted to one specific product, given it's a quality site and optimized well.
You can always test (cheaply or free) your medical report idea using public domain material like at Project Gutenberg or even wikipedia. People will definitely pay for a product even though they could find it for free somewhere else. Why do people buy books when the library is full of them for free? ;-)