Now I haven't seen anything convincing that indicates that cold fusion will work, but I also haven't heard of any significant investigation.
Cold fusion has been heavily investigated. There is one striking thing about all of the supposed "positive" results: they are physically impossible.
Suppose I said I had invented a car that ran on water, and that my claimed proof was that I had driven this car along the streets of a distant city. I give a talk on my results and show a map of the route.
A person in the audience interrupts and says, "Hey, I know that city! That's my home town! The route you've shown is impossible: you say you drove it between 4:30 and 5:30 PM on Tuesday June the 6th, which is in the middle of rush-hour, and you've shown yourself going the wrong way on half-a-dozen one-way streets! Why didn't you collide with anything?"
I reply: "This car runs on water! Weren't you listening? It doesn't collide with other cars, because it is propelled by water!"
You would be correct to suspect that you need not take my claims very seriously after that, and this kind of exchange is typical of cold fusion talks.
I saw Pons give a talk at Caltech, where one of my colleagues interrupted with the question, "Where are the neutrons? You say you don't see any radiation because all the energy comes out in high-energy alpha particles, but if you make alpha particles move with that energy through the palladium lattice you will get neutrons? Where are they?"
Pons answered: "New physics."
But alpha particles don't care what made them move, and more than a car cares what fuel it runs on. You can't just invoke "new physics" and say that the lack of neutrons or gamma rays doesn't matter, because you aren't really invoking new physics, you are throwing out old physics: you are saying that high energy alphas don't produce neutrons, even though that would require all of nuclear physics to be wrong.
So while I agree that new phenomena are often difficult to reproduce and we should be cautious about dismissing them on that basis, cold fusion, after twenty-five years of testing, has proven to be:
a) impossible to reproduce (there is no reliably reproducible experimental setup)
b) what experiments that have claimed positive results have always (to the best of my knowledge) required almost all of nuclear physics to be wrong to explain the absence of radiation.
I cannot think of any other phenomenon that eventually proved to exist that shares anything like this history of failure. Maybe Lister's work on sterile technique in surgery, which had a decade or two of rough handling? But even it was frequently reproducible, even if not universally so, and it didn't contradict any well-established, empirically founded, reasonably comprehensive theories of the time.