And as for funding, Batman had a credit card which I presume was untraceable, so...
Batman is constantly portrayed as a person who has need and use for an untracable credit card. Tony Stark hasn't been.
That doesn't mean it is implausible, but it still makes the whole "I'm going to keep the world thinking I'm dead" and subsequent isolation completely vague. If he had a credit card, he could have bought higher tech power supplies and repowered the armour that much sooner.
The desired storyline needed him cut off from his usual resources, otherwise he just has unlimited suits of armour. But it doesn't take the dare and put him back in the equivalent of a cave. So I found myself confused as to just exactly what his situation was.