Yes there is a case to be made about the elder son. In my Christain Fellowship we spent two weeks on this one parable; the first week we looked at how we can put ourselves in the shoes of the older son, and the sencond we talked about how, if we don't necesarily identify with the younger son, we probably do with the older one.
We talked about how sometimes as Christians we view that there are certain things we feel we have to do in order to recieve God's love. We have to go to church, not swear, follow the commandments, give to the poor....etc. And then we see/realize that there are other who are not doing all of the "required" things, and yet they still recieve God's love.
But the point that (I think) Jesus was trying to make is that there is no list of things you have to do to be loved by God. God loves all His children no matter what. And at the end of the parable Jesus never said whether or not the older son decides to go in and recieve his father's love, or stay out and get nothing.
Hope that helps!