There are a few of us that have replaced the front rim with an 18" rim, and we use the stock hub/brake assembly.  This simplifies the brake issue, as all the stock parts work.  This isn't always cheap however, as spoke sets are about $100, rims can be $ 100-$200, and if you can't lace and true a wheel yourself, the labor is around $100 to pay someone else to do it (and shipping if you have to mail the wheel to have it built).

The easiest change for you would be to install a 90/90-19 front tire, as that will be a tire that has less height.
http://www.bikebandit.com/tires-tubes/90-90-19-street-motorcycle-tires/t11lr4cd

Going to a different front wheel assembly is more complicated, as you can get into axle size, wheel spacer size, and brake issues.

And it is possible to install a front wheel without any brake, and this was common for the old school choppers - but that really doesn't  make a motorcycle that is safe to ride as the rear wheel provides very poor braking when you need to stop in a hurry.