hi, just got back this week from India. We booked the entire tour through a Delhi agency (and had many problems) ..... the local agency they used in Kerala was Marvel Tours. Delhi office (different agency) booked us on a non-existent sector and failed to re-confirm the flight; the local Marvel agent caught this (despite it not being their responsibility) and strongarmed India Air and the Delhi agency to sign over the ticket to Jet Airways so we wouldn't be stranded. The houseboat they booked for us was wonderful and the driver a very pleasant man.

Here're their details:
Marvel Tours
http://www.marveltours.in/
email: [email protected] , [email protected]

our overall tour was a "reasonable" budget tour, so I'm pretty sure Marvel can meet your needs ......