I recently was fitted for a rental DUI suit, and was amazed that I fit a standard large. I thought sure I would need an XL, per the sizing chart. I'm 6'3", 185, so my problem is not as extreme as the OP, but I can indeed vouch that the DUI suits seem work taller than expected.stevead:The telescoping torso on a DUI means that a 7 footer could probably get into a large if he was skinny enough. might not be a perfect fit but he could wear it.
I see that the OP has settled on an Otter suit, and I look forward to the review once he gets it. The one point I would add is he'll likely want to mix and match several varieties of undergarment to cover all diving conditions: Heavy (or perhaps multi-layered mid-weight?) for cold, mid-weight for temperate (adjust as needed depending on cold tolerance). In true warm water environments, I would just leave the drysuit in the hotel and rent a shorty.