OP -- if you are willing to payt for 2 biz class tickets, then staying at a Sheraton is not that bad..suggest the following:

1) book a night at the Sheraton....they will pick you up and drop you off...take a HOT shower and grab a nap....

then have them take you to the domestic terminal in the morning....

If you can, stay one day in BOM to break up the journey...this will also give you the chance to eat at "Peshwari" in the Sheraton...it will be one of the best meals eaten..