Steve,
Heck yeah, people build lots of different things on this forum! I built one and have enjoyed the way it has pulled and the extra room that I put into it. I will admit that it could be smaller but we are enjoying the space.
Your smaller wheels and shorter length will look wonderful with two wheels on each side. DO IT!
It will tow great, it won't be as mobile in the camping area. 4 foot tall will be plenty, and a couple extra feet in length will be very possible.
So the question is, what shape you going to build and what is stopping you?
Have a great time planning and start the sawdust as soon as you can. Whatever you do, it will be yours and it will be something you learn from and enjoy.
I wish you were closer, we could talk in person.
John