Back in the 60's & 70's we farmed 150 acres with a single 48-hp, 2-wd gas powered tractor. That is why I laugh when people talk about seat time. They have never spent 12-16 hours a day in the seat of a tractor. It also amuses me to see people spend so much money buying a tractor large enough to run a farm and use it for 10-15 acres. If you have the money to spend by all means go ahead and buy one of those large tractors. If you are short on time and can afford it go ahead and buy the larger tractor and implements. As for myself, I am one that goes for the cheapest way to get the job done correctly. For 11 acres I would get a smaller tractor, light duty rotary mower (you're not clearing ground), and a zero turn for mowing. I cannot see mowing a yard with a 4000-lb tractor. Can you say ruts? Maybe your soil type would allow it but here in KY with our soil it would be a disaster. The people who have tried to use even 25-30-hp tractors to mow end up getting rid of the finish mowers and buying a machine actually designed for mowing grass. They simply screw up the yards BAD. So why spend the money on a tractor finish mower?
So, since I am spending your money I would get a smaller tractor and use the money saved to get more implements. Then I would get a GOOD zero-turn mowed DESIGNED TO MOW YARDS and use it for....mowing the yard. Your yard will be easier to take care of. You will mow more often (Can't mow the yard today honey, the tiller is on the tractor!). I have no experience with a flail mower. I am sure they are good for some applications but I do know they take more hp and the tractor moves slower. If you mow the pasture once a month a 25-30-hp with a 6' rotary mower will do the job more efficiently and quicker. Why spend the money? Have mowed some of our 20-acre pastures with my 22-hp Kioti and a 5' mower when the big tractor was down. Slow but got the job done.
Just my 2 cents from somebody who likes efficiency and saving money.
RSKY