Excellent idea- and nice to think out of the box considering I never thought of putting a front rack on this bike. I like the idea and it makes a lot of sense, too. Thank you!
If you are having this much trouble with it the wheel has some issue which is compromising it's structure. You can try to have a shop check it out well and properly tension it in hopes of it coming around but a new, properly prepped, wheel is the one sure cure.
A hand built wheel is the true cure all; Raid Transit is going to be having a huge hand built wheel blow out this winter, details coming soon.
If you can afford a new hand built wheel go for it. However, if you're looking to save some cash, a brand new non-human built wheel and evenly distributed cargo (i.e. front rack) will very likely be your solution. You might need true it at first since the machine isn't perfect, but once it's done, you're very likely set for many miles. And not to brag, but I'm at 11000 miles for 2011, and just re-greased the bearings for the same set of wheels.