Well, this is a HU idea against weak-tight opponents, but it seems to work fairly well.
Basically, I start off raising pretty much according to Harrington's recommendations (my new HU guru!). But if I notice that my opponent is consistently folding to raises (less than 20% calls), then I make a switch: In position, I just start typically limping with all premium hands, but I start raising the BOTTOM 30%. Of course, if they suddenly start calling, then you have to go back to a more solid strategy.
Also, if they do call (as long as you haven't been raising them to death with this), almost any face card is a scare card for them. At least for me, I'll just fold my 72o unimproved if my opponent makes a solid bet into me, but to a check, a continuation bet is often pretty promising.
As I say, I certainly don't recomment this idea against more aggressive opponents or those who'll call any raise, but it does seem to work against players who are a bit too weak-tight PF. And it leaves you your strong hands to actually play, where there's a pretty good chance that they might spike middle pair when you have top pair, stuff like that. That was really my reasoning behind this move: I just got tired of not being able to play my strongest hands in position against some opponents.
One other thing: I'm much less inclined to apply this strategy out of position, although it still has some potential. It just bothers me much less out of position to just get a limp-fold to my KJ.