I thought it was an interesting point... I hope I'm not repeating someone else.
Also true about the people of that era, they were generally by western standards very fit but much thinner then what we consider to be a gym-made body. Extra fat was reserved for people with money. On the other hand there is evidence to suggest that Jesus was from a wealthy family, and that the whole poor concept was introduced by the author over 80 years later IN ROME in order to allow the story to propagate. There is a big difference to the Romans between a story being told IN ROME about executing a poor powerless religious figure, and one from a well-to-do family. The Romans may have reacted very differently had the author told the unvarnished truth, also the impact of the story is diluted if he were an aristocrat, people would be blinded by their prejudice against the rich and would totally miss the moral and his true message in the sacrifice. So really we may never know what is truly 'correct' regarding his physique and the true nature of his execution... or in fact even if he was executed.
So as in all history, I think this image needs to capture some of the feeling of the event, that's important... though one really big issue is how clean he is. AFter his ordeal, staged or real, he'd be DIRTY... like really dusty and uky. Also, it's likely jesus himself was of darker skin. The western-centric view of jesus... well... it's westerncentric. lilly white... he'd stand out like a sore thumb in the local population. Though again... who knows for sure.
Nice work! I like the fact you tackled a controversial subject matter!

Ian
PS. I'm not trying to offend anyone here. I personally believe that we know only a small part of what happened over 2000 years ago. The recent unveiling by the national geographic society of evidence suggesting that Judas was a traitor at Jesus's own request shows how little we really know... thus making images like this are always best guesses anyway... that's all I'm getting at.