Tim Weisberg would have been an Excellent Foursider.There are a lot of "lesser known" A&M acts that put out enough music to make a Foursider. Rick Wakeman, Tim Weisberg, Fairport Convention, Spooky Tooth..... they could have had a sub-series called "A&M Artists that Didn't Sell FOURSIDERS!"
Just a reminder at the beginning of the post i gave the time period of between 1973 to 1988 or 89 just before A&M was sold to Polygram I agree Janet Jackson would definitely fit in.Depending on how far into the 80s you wanted to take it.... Janet Jackson would have qualified. It might have been a good way to sell some of her "old" tunes that people missed. Package them up with some newer stuff.