I'm not sure about the loaf's-end meaning of 'nobby', but the application of that word as a nickname for people called Clark(e) has probably nothing to do with Indian words at all.
�Nobby' has been an adjective meaning �posh' since the 1700s - ie belonging to the nobility (abbreviated to the nobs). Men who worked as clerks...ie pen-pushers...in the City obviously had to be well-dressed, wearing suits, bowler hats etc. Clearly, people - and maybe they themselves - thought of them as being a cut above their neighbours the brickies, dustmen etc in their rough work-clothes.
It's also possible that the Clarkes who moved into cities thought of themselves as 'better' than their country cousins, so they changed the spelling to make themselves seem rather more up-market.
The surnames Clark and Clarke are just variants of �clerk', so the idea of poshness rubbed off onto them, too, whatever their job...hence Nobby Clarke.