LOL. If you did it, I would just buy a new rear rim. You're already going to have to buy new spokes and pay to have them put on - this way you can go back if it doesn't work out.

However, owning a bike with an internal derailler that I use for winter riding, I would ask - "Why??". I'm trying to avoid my gears getting iced up, or absolutely covered with road salt and sand in winter riding on the roads here. But I gotta tell you - I have ridden my IGH bike in the summer several times (with summer tires, obviously) and it's slower to accelerate, the gears are spaced further apart, it's more work to pedal compared to a derailler bike. And since it has a chain there's really no maintenance advantage. I actually bought a 2nd road bike for commuting in the summer because I like the gearing (plus the drop bars, and at the time the ease of getting drop bars in and out of my car) better.

If you REALLY want to upgrade ;-), you should get one of the latest bikes that has an IGH and a belt drive! :-D :-D I am serious though - you'll still have some of the slight disadvantages of an IGH, but with no chain to oil or get grease on stuff you'll have less maintenance and no chain oil getting over stuff. In my opinion, owning an IGH, there's not much advantage to it, and I find the supposed maintenance benefits (with a chain, different with a belt I think) highly, highly overrated.