Our T5 suits us brilliantly. We have a tin roof (no pop top), and units down the drivers side, which keep a weeks food next to the fridge, and a wardrobe at the back for a weeks clothes. Under the wardrobe is the leisure battery and electrics etc, and in the space between wardrobe and food cupboard is the water tank. A swivel passenger seat gives seating for 3. If you are going to have a full width bed, just consider where the stuff like leisure battery and water tanks can go. There are solutions (water tank can go under the van), but everything in a camper is a compromise of space over storage over ease of use.
There are only 2 of us in our van (and 1 or 2 dogs), and we are not tall, hence no need for a pop top.
Try some out at van shows etc – there are loads of combinations and there will be one to suit you. Vanfest is not far away in time and is at Malvern and is worth a look if you are local.