Dell have a policy where they do not sell caddies without drives, but are making an exception due to the hard drive shortage.
They're not too bad to deal with half the time, or too expensive, so if you get desperate you can give going direct ago. You have probably dealt with some bad reps, managers or entire teams before so I can see why you want to avoid this.
We have never ever faced a issue when buying caddies on their own directly from our account manager. Im sure it just comes down to how your account manager is doing for the quarter.
I see Stallard a lot on ebay. But having checked their prices on things over the years they never seemed to be really competitive. Although in a pinch they probably have what you need and can next day air it at a reasonable cost. I would bet their caddy prices are the same xbyte.