It is possible to do a side-scroller for well under $500K, however it is very likely that a 'noob' would end up spending well over $1M (assuming one has the money!) by sheer lack of experience.
I suggest starting smaller: scale down on the amount of levels, reduce the amount of features, stick to straight 2D if possible, and try to learn and do as much as you can on your own.
The project probably won't be profitable even then, but the experience you'll earn from the effort will cost you much LESS than $500k, leaving your hypothetical super-mega-funding in your pockets for when you have more experience and can actually turn it into a successful project.
Perhaps you're right. I've been mulling over this particular project in my mind for a while now, and I really don't want to screw it up. I do have another idea that would take less money/manpower and I should start with that first.