If pores are needed there are ways to obtain them. I would suggest to also try looking on the so-called "pore forming agents" which are often used in heterogeneous catalyst production. Alkali metal carbonates are also used for this, for example.
However if hydrogen loading alone is able to form new pores and voids in a certain material then the same material may not be able to hold structural integrity for very long or even at all. This is one of the problems that plagued reproducibility in Pd-D LENR as far as I know. For example, Palladium expands significantly under loading (~10% volume) and eventually cracks, pulverizes, relieving pressure that may have formed inside the pores and crevices formed under loading. This is why pure Pd rarely worked and why only that from certain producers, which contained specific impurities, did.
With this in mind, it is also worth noting that high loading as Edmund Storms also observes - at least for Pd - is only needed initially to permanently alter the material. Once the proper cavities are formed a high loading is not necessary anymore. So this could be hinting at the possibility of being able to form a properly working material before hydrogen is even added.
On a loosely related note I wonder if by coating a metal that expands a lot when absorbing hydrogen with a very hard one (perhaps a non-metal, like a proton conducting ceramic) that does not expand at all an even higher pressure at the interface between both materials could be achieved.