Haven't had the problem myself but I have read many threads on this subject. It is reccommended that you have atleast 12ga spokes. Also to have the newer 9-bolt sproket instead of the six. This is a common problem, I would check my local bike shop about having the wheel re-spoked, may be more cost efficient than purchasing a new wheel.
the only way i know of that they could bed is if they are to loose or your rim is bent. sometimes they break inbetween the the padding you put on both sides of the spokes so grab the spokes and try to move them. in the past i had a 5 hole sprocket and kept breaking spokes. i went to a nine whole sproket and havn't broken any spokes since. is it posible to show us a picture of what it is doing?
Its also a function of how you ride your bike - high kerbs and such under power are such a bad idea.. the wheels arent designed for that sort of stress.
Its worth beefing up the spokes and also having more attachment points for the sprocket... its also worth looking at your riding style and being as smooth as possible - snatchy means stress which means more fuel used and will be detrimental to component wear
I run a Dax 70 on a Trek 7000 Mountain bike with the HD 9 hole mounts and have not had any wheel issues at all....I weigh about 160 lbs. I haven't abused the bike but I haven't babied it either. Perhaps, getting the wheel done right one time (trued... all spokes tightened as they should be...sprocket properly mounted)...and your problems may be over?
I did have a problem with my back rim. My spark plug went bad and the engine misfired and with all the jerking my back rim got a nice wobble to it. Nothing a quick trip to the bike store can't fix. This does make me think about getting an extra front and back rim so I don't miss out on any ride time. I'm going 30 miles a day round trip to and from work. I never thought saving $200 bucks a month on gas could be so fun.