dw06,
My passion for making Elderberry Wine and Elderberry Jelly every year is one of the reasons I asked "The Hammer" to have a forum for Gardening and Home Wine Making. Happily, he agreed after a few times. GB's generosity with sharing this great website for a multitude of interests will hopefully keep it growing.
If you plan to start some Elderberry plants on your property, maybe I can give you a few pointers on what to expect. Before all that though, I think you should have solid plans on where to put them and what kind of soil is available. In my experience, there is a tried and true method of propagating Elderberrys, and it almost guarantees MONSTER bushes in less than 5 years.
You should probably also know that there is more than one type of Elderberry available. Some have Green Stems and some have Purple Stems (don't ask me which is which). While it really doesn't matter which ones you plant, one type comes in about two weeks before the other, and if you have both, you probably can plan on a soilid three weeks of picking because of the staggered ripening.
Also, using Mir-Acid (Miracle Grow for Acid loving plants) will really push production.
Site prep for me includes digging a hole and mixing the soil with Hardwood Mulch, so there is about a 50/50 mix.
I know it may sound funny, but some years I have more Elderberrys than I know what to do with. And I constantly run into people who ask me "what happened to all of the Elderberrys, they aren't around as much as they used to be." Obviously, people don't look for them at the right time of year or it is just a passing interest. Take it from me, they will always take a bottle of wine or a jar of jelly, but they will hardly put the time in to try to find them when they are blooming or just about invisible.
I got another Shopping bag full this morning, the first bag yielded about enough for two batches of jelly. Out of this bag full I will probably keep enough out for roughly two gallons of wine, and the rest will go for jelly. Even though the wine should be done fermenting by Christmas, I like to let it age for about a year, so it will be ready for Christmas 2009.