Dreaming, When I purchased my longarm I had a stack of UFO's that I thought would take me forever to quilt all of them. In less than two months I was out of UFOs and still wanted more practice. Thankfully, I have several friends who are also quilters, don't own a longarm, and they were willing to trust me with their lovely projects to quilt to continue my learning experience.
If you don't know a beginner longarm quilter, you might check with a local Guild or your local quilt shop, or local machine dealer, to see if they know of someone new to long arming and willing to do it for free just for the opportunity to practice.
Keep in mind, being new means the work may be a little less than perfect or simpler designs (but in my case was still better than if I did it on my domestic machine). Also for me, practice doesn't mean I'm still learning, it just means I can't create a top fast enough to be able to use my longarm every month, and I want to be able to "use" the skills I've learned frequently so that they become second nature.
If you were closer, I'd offer to take on a few for you, but experience has taught me that shipping can be pricey.