Seems like to me, putting a tailwheel on a 150 is just building a heavier 140 with less performance, Why? If you put in a O-320 you have a plane with performance but no room or useable weight. Plus you'll have a bunch of money and time into a plane that could be replaced by a whole bunch of more capable planes in that price range.
Don't get me wrong, I love 150's. C150's actually land and get off the ground pretty fast. I have a climb prop and I can land and take off at U77 before the first turn off from a dead stop. Google Earth is showing it as about 650 feet and that's at 4500'. Works OK as long as you don't have a tree or power lines in front of you. They are great little planes and a lot of fun but I don't see spending a bunch of money trying to make one into something it's not.
One thing I like about a 150 is that you actually have to learn to fly in a 150 because they have a lot of nothing! No power, no climb. Everything has to be right or they just don't go. I had one guy ask me if mine would go over 8,000 ft with two people

. He told me he looked at one and he said it wouldn't.
If you guys want a 150/150 there is one in the project section of Barnstormers for $12,500 right now. Supposed to have a low time engine but no engine logs to prove it. You will never build one for close to that.
Bigger tires would be nice but I wouldn't want to lose any of my 491 lb payload. It's a lot cheaper to learn to land slower anyway.