Nick - technically you can make the doors any size you like providing the hinging arrangements are adequate and, if made from single sheet material (as opposed the skinned frames), the material comes in big enough sheets. Not withstanding advice already given in the thread about tall cupboards, if you think tall doors are the look you want then go for it.
If you have access to a router why not make a jig (2 strips of MDF each about 100mm wide and slightly longer than the height of the doors, held together with strips of timber at each end - the gap between the 2 strips wide enough for the router guide bush). With a suitable cutter in the router cut a series of parallel flutes up the doors stopping short, say 120mm from top & 160mm from bottom of the door, to create a panelled look. MDF primer, undercoat then good quality eggshell paint, applied with a radiator roller - they'll look great!
Fit the cupboards out with commercial (shop-fitting) chrome racks, baskets, wire drawers, etc.)
Huge chioce of hinges available including, concealed (like kitchen cabinet jobs), easy mounts, etc. depending on your skill level to fit. Check-out
www.woodfit.com for all the bits you'll need.