The original poster required a swim platform / sugar scoop transom. That rules out most boats from the 80's. Some notable exceptions are the O'day 35 (1986+) and the Newport 33 (1985+, but not all have them). Note that the only difference between the O'day 34 and 35 is the swim platform. I think the Hunter 'Legend' series from the late 80's also has a swim platform, but I'm not sure
In the 90's many more manufacturers added the sugar scoop, but manufactures like Tartan and Sabre were late. I don't think you will find one of those with a sugar scoop for near $50K.
My last comment is that while I understand you wanting a boat less than 10 years old, when you start seriously looking you will find that some 10 year old boats are trash, and some 20 year old boats are mint.
IMHO (and I am prejudiced) an O'day 35 would be a good choice. You can find them in excellent condition for under $40K.
Having experienced the sugar scoop transom on the Freedom 38, I really would miss one, but I suppose I could cobble together some kind of (ugly) bolt on platform to serve the same purpose.
I will be opening up my search to include the 1980s as well.