If your bunny isn’t a jumper or climber, a playpen can work as a great ‘hutch’, even as an add on to his current cage would could still hold his litter box and food/water bowls, but also have access to the playpen. If he would be inclined to jump out, you could peg a sheet to the top to prevent that. That’s probably the easiest way to offer more space.
In terms of actual hutches, I’m not a fan of any I’ve seen in stores here. I bought storage cubes and made my own cage, it’s about 1.8m long. I open the door to the playpen when I’m home, I don’t trust them when I’m not home
You can buy the storage cubes online from the Guinea Pigs Australia shop, or if you live in SA, Browse In and Save stocks them, I don’t know about stores in other states.
In their cage during the day, I leave baby toys such as plastic baby keys, plastic stacking cups, wood chews, wooden barrel roller, a wooden bendy bridge, cardboard tubes (with or without hay in them).
