Thanks for all your input.
Air Deccan (a LCC-style de novo firm) has BOM-GOI/GOI-BOM for appx. INRs. 2600 one-way (regardless of nationality/residency***).

And DEL-BOM/BOM-DEL can be had quite reasonably too.
Mixing and matching Jet Airways and Air Deccan worked out quite well and getting same day (or one-day in advance) tickets should not cost more than INR 9,500 one-way (for NON-Indians) since the BOM-GOI sector can be had for $101 one-way while BOM-DEL sector can be had for approximately $110 one-way.
As a further note, Air Deccan is selling a promotional scheme of any 30 one-way segments (to be used as you please) for INR 50,000 upfront. Could be quite a deal depending on the routes being flown.
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*** Apparently foreign nationals with work permits/visas/residency for India should qualify for "Indian"-only fares in compliance with the local laws. (I was also amused to discover that there may be the possibility that some persons can be "state subjects" -- in the case of at least one state of India -- and not yet have Indian citizenship/residency.)