One of the problems I've found with clinical trials is that the PIs set it up for 'pristine' candidates to keep the signal as clear as possible. Once you're heavily treated for cancer you can kiss lots of them goodbye, regardless of the potential efficacy. It's also super hard to find a good trial for a specific patient...clinicaltrials.gov is helpful but it's still a mess because everything is free-form text. Emergingmed and others have tried to normalize and 'wizardize' the search, but they miss things in their normalization of the study focus and criteria.
Also as I mentioned above, there are very few trials for 'cancer', they are almost all disease-specific because the oncologists want to know how it's going to affect their specific situation. This multiplies the surface area that needs covered in a trial, increasing the cost (and delay).
Allowing patients, particularly terminal ones, to make informed decisions on treatment that hasn't been approved is morally correct in my opinion and definitely a way forward. Ideally each little 'experiment' would be tracked in some way to start creating enough of a sample size to draw some statistical conclusions. This could then drive interest in running a full set of trials on the therapy.