I made my kitchen island a few months ago.
First one so there are mistakes; but, I'm working WITH them. I cut the counter top too short so I'm imagining adding some type of ends? or maybe just nothing. I was going to order another 8' x 4' piece however that'll look weird with 1.5" length sides and 3/4" side sides.
I had enough space for 4 chairs; but, I'm totally in to utilizing as much space as possible so i added a book shelf on one end and a wine rack on the other.
Now, back to utilizing as much space as possible...I know I'll never have a need for 20 bottles of wine so i took out the last 3 racks and made an area for veggie baskets! I LOVE it!