The Deere quick connect forks for the 4xx loaders go for $999 at your local JD dealer. They are adjustable, replace the bucket, take about 2 minutes to put on/off, and take a big chunk of change out of you pocket!
You can get forks that attach to you bucket for about $450. They work good if you are only getting forks for the occasional use. If I was going to use forks every day I would get the JD Forks that replace the bucket.
PLOWER , I'm using a set of clamp-on loader forks on my 4100. I got them thru ssb.tractor.com. Very handy to have around. Easy to use. Can put the weight quite far out in front of the tractor though. Definately need to use some type of rear ballast. I use them mostly for picking up and moving log lengths. A lot quicker than chaining them up to the bucket.