Why do we have so much neurological research on and treatment designed for dyslexia, yet less so for dyscalculia? I know next to nothing about intervention methods designed for dyscalculia, or 'dyslexia with numbers', as I have heard it colloquially referred to (considering how obscure the term seems to be compared to its language-related twin). I have also read that dyslexia and dyscalculia often occur in conjunction, and both seem to affect the population at equal rates. Yet I can find far more literature and neurological research on dyslexia than on dyscalculia.

Is there a reason for this? And what do we know about dyscalculia from a neurological standpoint, as well as a treatment standpoint? (By 'neurological standpoint', I mean what do we know about neurological causes and/or areas of the brain that appear to be affected in those with dyscalculia)
This website http://www.aboutdyscalculia.org/causes.html provides answers to some of the questions you posed, although I am not sure it is the most up to date information. I would always advise one to do research on more scientific grounds.
From my perspective, dyslexia has also been more studied than dyscalculia as its impact in academics seem more easily perceived thus easier to diagnose. Furthermore, I think that there is a social component to the issue as people often accept with ease someone struggling with mathematics but respond with more preoccupation towards difficulties with reading and spelling.
I leave you one article that may be helpful to you. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3514770/