I'm a consistent monthly contributor to MD, and from my perspective, the big tombola-type event would be fantastic (Option 1, variant 1). To me, I don't really spend the credits terribly often because I don't feel like I need very many things from the shop anymore. But, I still let my credits build up as support and on that basis of "I might have a use for these one day..." So, I think something really big that come about from continually doing this, but not too frequently (200 instead of 100), would be like an extra incentive to keep on. AND, say we get up to that point and get something really awesome - further incentive to do it again.
Issues... Well, I certainly understand that option 1 isn't the most friendly to non-paying players.. but, I do not think that a Free Credit lower limit ticket is the way to solve that, because that just means double prizes for people who buy credits AND use free credits, and that's not really balanced either. So yes, it leaves the possibility for free players to get involved, but I think realistically they would not become involved because 200 is a LOT of free credits. I do NOT like a rift between paying vs. non-paying players, though if this is the path to be taken it will likely be a wonderful reward for those who contribute the most. And of course, the option of giving people tickets to the second level for things other than money would be an option.
One more thing to consider is that players who may be unbalancing things due to their extreme use of the item shop (myself included most likely), will be the most likely ones to get the bigger prizes...just making that gap bigger. Food for thought.