I personally feel some of these fruits will suit Indian taste and might be commercially viable.
Few to name are Rambutan, Lychee, Longon and one more very similar to Longon (don't recall the Chinese name. The fruit has sub pieces like orange). All these trees are relatively care free and require very less attention. This year I have plans to plant all of them to see how they grow back in Maharashtra. I own a farm land Near Aurangabad.
There are few nicer varieties of Mangos available.
1. Rainbow Mango (Mahachanok) of Thailand. Looks nice, has very nice fragrance and good taste, weighs uniformly to 300 grams per piece. This can be to some extend compared to Alphonso Mango which weighs 250 grams per piece. Rainbow mango has bit lighter coloured pulp as compared to Alphonso. The seed is thin hence more pulp.
2. The second one is Chinese King Mango of Tiwanese origin- 1200 grams per piece and is sold expensive - close to 8-10 Singapore Dollars per piece. This is also known as Golden Queen mango. See newbielink:http://www.rarefruitnursery.com/products.php [nonactive] and search for Golden Queen or Jin-huang Mango
Other fruits which might already be known are Thai Pink Pomelo, Chinese Golden Pears and Avocado. Pomelo (citrus family) is found common in Andhra – that’s what one of my acquaintances told me.
Some more fruits which have peculiar taste and might be appreciated only by a section of people are Passion fruit, Star Fruit and Durian. Durian is national fruit of Singapore, look wise and texture wise is similar to small Jack Fruit. The odour is intense and mostly unbearable. The fruit is not allowed to be carried on Public transport and one cannot carry it along in hotels/lodges due to strong odour. You will either love it or hate it. The taste is intense of extreme ripe mango and Jackfruit. Even these are sold outside of malls in stalls and not inside.
Refer newbielink:http://www.hotelclub.com/blog/10-must-try-exotic-fruits/ [nonactive]
If you own a Green House, you can try KIWI fruit which is native to South China and widely produced in New Zealand, but found abundantly in stores world wide and fetches handsome price. See Wikipedia for more info.