I am surprised you have not got one in your collection yet, when I bought my first one in 1983 at an auction in Warwickshire UK they were a very scarce tractor, I knew of one other original styled 25 at that time in East Yorkshire, both these tractors came over to England on the Lease Lend Scheme in the war from the USA, mine was new to Derbyshire War Agricultural Committee and I have the original registration document which shows it was new in 1942, so I am sure it had been hanging around in the Racine for a long time not sold to a US famer and eventually put on the boat to England.
Interesting you mention the wheel size, yes mine is on 28inch F&H wheels with the original US front tyres still fitted which it was enw with and the owner had put one new set on the rear at the end of it's working life, he also had a styled Pacemaker and found it more useful to use than the 25, so the 25 never did a lot of work. The other original import tractor in East Yorkshire is on 32 inch F&H rear wheels and looks so much taller.
On my early 1990 trips to North America I never saw any styled 25's for several years, eventually seeing several in Western Canada makes me beleive the majority of them sold out there for working the Prairies, the past few years we have seen them appear down in the US amongst Massey collections and several more worked their way across the pond here too.
Here is a photo of my Lease Lend tractor which has been in my collection 29 years and one of my favourites.