Some plants can be transplanted, but not all can. I doubt very much that [tall] corn can be readily transplanted due to the roots. Seedlings can be transplanted; I used the plastic bag/wet paper towel trick this year to get them started. if you try the paper towel method, make sure it is single ply, or separate any double ply paper towels.

Corn can be tempermental. My neighbor did fine last year [absent pests] growing a row of [mixed] corn all crowded together that shot up to 14ft tall all fertilized with chicken poo, but probably the wind was favorable to her. She got her corn in before the late frost last year and it survived both the frost and a drought-she waters her garden. Mine wouldn't even sprout last year due to the drought.

2 years ago my corn was maybe 6-7 feet tall, much of it didn't produce anything. This year much of my [Bantum] corn is between 7-10 ft tall in the same location. I weeded [garden hoe scraping the surface, but not too close to the plants] the garden better this year (Really, I did), but I think the main difference is we had a lot of rain this summer.

A block of corn doesn't have to take up a lot of space, especially with just 20 stalks. instead of say a 20 foot row, you could have say 4 rows (3 feet between each row) of 5 corn (1 foot apart)...anywhere from 36-90 sq feet depending on the garden exterior. if you have something that grows fast (raddishes) you probably can put them between the corn rows to save space.