To the OP & all others who are concerned about BAD ESN phones,
1) There is no way for sellers here to offer latest smartphones for such low prices if some of those phones(if not all) are not BAD ESN.
2) The second thing, the people who are looking to use these phones in both India & US are very few(I can even say negligible, I only saw one person requesting a phone that can be used both in India & US in Handset request thread in this forum). If a particular person wants to use in that way he can always check with the seller, I don't think any seller here will lie about it. And how many days you gonna be in US, may be few months at max, hence you tend to get a SIM from some Pre-Pay network operators over there(almost all of them are GSM based) and if you buy a phone of Sprint & Verizon, you aren't gonna be able to use it with any GSM operator in US no matter if it is a Clean ESN or BAD ESN, of course you can overcome those restrictions in some phones.
3) Contrary to the some people's assumption that the maximum percentage of BAD ESN phones are being sold to buyers outside USA, most of the BAD ESN phones are bought by US buyers themselves as there are many other network operators that accept BAD ESN(note: BAD ESN is doesn't necessarily be a stolen phone) phones of big network operators like Verizon & Sprint. And you may not know, but there are lot of ways to make them work with the same carriers too. And there are very few operators that are using CDMA outside US.
And to wrap this up & with due respect to OP, I too think & agree with some people who said this topic or thread is unnecessary except for a good reading of a nice fiction story by Genius, because we all know how the sellers import items from US to India, asking their source(or from whom they buy) is just not right, as some one pointed out correctly that you are not gonna ask a retailer in your town from which wholesaler they are buying & at what prices, if you do I'm sure you'll be show the way out of his shop, they why ask here.
Those are my two cents, sorry if those hurt any one.