Did you watch this programme last night on Channel 4???
If you click on the link above, it will show you a brief clip of some mad vegetable growers that not only HAVE to grow massive veg, but others who HAVE to grow extra long veg e.g. a 12 and a half foot parsnip! One chap hasn't been on holiday for 20 years + and another won't retire from growing his extra big / long veg until he isn't given the "best in show" award - an award he has won for the last 10 years in a row!!
I would rather do what I do, sow the seed, watch them grow, pick them when they look about the right size & eat them! Mmmmmm - yummy.