Speaking as a non-professional, I have seen no such detailed datasets.
Your research should not depend on clueless strangers, though. My first hit on Chinese statistics was: http://www.stats.gov.cn/english/statisticaldata/ , and I'd think they are worth exploring. Same for India.
Gathering detailed income data is fraught with difficulty on many levels: the ones with access to the high-fidelity data (local tax authorities) won't talk for a host of reasons, apart from confidentiality (quite often they won't be bothered to help other government agencies), while aggregation over villages/counties/whatever lowest-level administrative units is not something in high demand from national and supranational decision-makers. I leave aside the obvious problems of tax evasion, non-response, and outright fabrication.
Thus, for countries with less than well-funded statistical agencies, one is forced to look for proxies.
The usual proxy is electricity consumption; while the utilities are loath to give outsiders access, as a rough proxy, one can simply look at the night lighting: http://geology.com/articles/satellite-photo-earth-at-night.shtml.
I'd recommend against turning to land use data - they can't tell you much about city-dwellers or income levels. You can ask folks at GIS SE for details, though.
Access to sanitation is another proxy (albeit a non-linear one). World Bank, local authorities, utility companies, food inspection agencies can possibly serve as sources, I'd guess.
Whatever you do, please remember to compile a list of references, prior and related studies, validate and cross-check your data. Ideally, you would do an on-site survey for that (assuming you have got some money to spend). Beware of systematic bias creeping in (it will!) without you noticing or telling users of your data.