Saw a conversion set (B727) on eBay for $2. TWO DOLLARS. I had to have it.... Shipping was only $6. When the stuff arrived, it turned out there are TWO sets! The sheets were sandwiched together.. So for $8 grand total I have this:

It even came with a nice thick sheet of styrene. I can use it to make bulkheads and what not. These were made by Griffin. I had never heard of them. I have no idea how accurate these are, etc, but for four stinkin' dollars a piece I'm happy to roll the dice.
As luck would have it, I turned around after buying these and found ANOTHER, this time by ATP. A little more expensive but still what I thought was a good deal at a little under $13 after shipping.

ATP. Definitely know them! Quality stuff. I don't know anything about this conversion fuselage though, but I imagine it's "better" than stuff in main stream OOB kits.
On that note, if anyone knows literally anything at all about both the ATP and Griffin sets then regale me, please.
Not pictured: another sealed Airfix Heracles. I only paid $14 for it.