By way of back ground, my club's course has four sets of tee markers on each hole. The holes have 3, 4 or, in at least one case, 5 separate rectangular tees. The card shows five sets of tee markers, black (7011), blue, white, green (5253) and a black/blue mixed set. In addition we added a mixed green/white set and a mixed blue/white set, initially for senior inter-club league play, which are also sloped and rated and so anyone can play them as complete courses. Several observations.
In setting up the combinations for the senior league play the focus was not so much on the overall length of a particular hole, or the length of the course as a whole, but rather on getting some of the seniors (who don't hit the ball very far) off the tee and into the fairway. Thus, we chose the more forward tees, even on at least one very short hole, where we felt necessary to make sure everyone could get his drive over forced carries, up hills, and past the dogleg corners.
Second, I like the idea of playing from different tees from time to time for variety. I'd like to see some of my long-hitting buddies go from the shortest tees on certain holes, because those tees will bring hazards potentially into play (off the tee) that they don't normally have to deal with. As a short-hitter, I'd like to play some of the long par 4s from the very back tees from time to time, turning them into real par 5s for me. The difficulty with making up hodge podge courses like this when playing for fun is that, as I understand it, you must post your score as played from the entire set of tees for the course from the longest tee (e.g., black in our case) from which you played, which has the potential to artificially lower your handicap. A solution would be to publish the slope and rating for each hole, and then let the golfers calculate the total for various tee markers from which they played. The difficulty, of course, is that this approach is just not practical under the USGA handicap reporting system as it is set up today.
Finally, from an architectural standpoint, I think I've learned that you cannot make all of the hazards play the same way (come into play) from different tees, so you design the course essentially for one set of tees (the longest?), and then let the balls fall where they may when play is from shorter tees. Some might use this as an argument against having multiple sets of tees, but as a practical matter I don't see any other choice for the club/course that wants to be playable by a wide range of golfers.