Wow - i mentioned in another thread aboot doing a project similar to yours. Its a really great looking machine y made there. I considered the use of 15" car wheels as well but figgered id get kicked out for suggesting it, instead using cub cadet or wheelhorse tall tires for all 4 wheels. I dont think id go as high as yours, mainly for the possiblility of doing a coil over type suspension with a differential axle in rear, using a 2/3 link in front an rear, just high enuff to be different then a normal mower. I currently am in the process of tinkering with like 3 other tractors and building a larger shed to do all this work in, then ill be able to get my welder n start fabricating.