I've never seen it, but an acquaintance of mine (back in the day), by other peoples accounts, had a wiffle/football field better than that guys and probably not as good as the Fenway one.
The kid's older brother wasnt much of an athlete, but LOVED sports. He was probably like 16 and "head groundskeeper" and umpire in little league. He would be watering and raking our little league field (which was pretty sweet) meticulously (like the little dirt between the foul line and the grass. He also asked my dad, who officiated several sports, for a referee's equipment catalog so he could order an inside-the-shirt-chest protector. The forearm mounted league one wasnt good enough.
Anyway this kid had a field with a Minneapolis baggy fence, played the national anthem on a boom box, and made people wear old little league uniforms.
One day they wanted to play football and he said "not yet". he spent about an hour or two lining the field complete with diagonal stripes across the endzone, 2x4's as endzone pilons, and PVC fieldgoals.
On to my first hand wiffle experience. That portable mound they have is GENIUS. My grandfathe would get pissed at us for wearing out the grass. Also, me and my cousin "juiced" the balls by wrapping them with duct tape, which makes them go at least twice as far for HRD (home run derby).
So who has a sweet yard for this?
BTW, there is a league that plays at gravelly point (just north of reagan airport)