The only snippet I have, other than his being the composer of the magnificent Gajavadana in Thodi, is that he belonged to the post trinity period. Can anyone shed more light? There doesn't seem to be much info on the internet
kumAra eTTEndra bhUpati if memory serves me right, is a royal composer and an subramaNya upAsaka. A sprinkle of his compositions are avaialble with notation in kr.timaNimAlai of rangarAmAnuja aiyyengAr's book. karuNAnanda (nIlAmbari - a vINA-vocal rendition of padmA varadan is available at: http://www.vipanci.com/music/music_player.php) is a popular composition of his.
IIRC karuNananda was also sung by Sri Shriramlumar in one of his vocal concerts in Chennai last year or thereabouts. A number of kumAra eTTEndra's songs incl. karuNananda are also listed in the SSP where he is referred to as kumara ettappa maharaja.
maharajas comp in thodi gajavadana is being popularised by t.m.krishna. its a master piece. off late sandeep narayanan a rising star among the younger generation of carnatic musicians disciple of sanjay is also singing this kriti often