I want to mention one point essential in the reselling plans as well as in shared hosting, I mean CPU increase, usually reselling/shared plans have enough disk space and bandwidth, it's CPU limit that makes sites upgrade to vps.
And I recommend to get a reselling hosting provider who allows for the CPU level increase in their reselling plans, they track the total CPU level committed to each server and increase it when it's necessary. I know this feature is enabled in Utropicmedia.net reselling plans, there should be other providers allowing it.
I think that anyone should post through his experience. And that doesn't mean that web hosting provider great at all. I think that it good for you not for everyone. I sympatize with HostWW.net and Site5.com. They are great reseller web hosting providers in my opinion.
There are many options now. Some of the first hosting reseller programs are still very active such as viaverio and alabanza. Otherwise lease a dedicated server and drop your cost per hosted site even lower.
For the ultimate reseller look for someone who sells billing systems with a discount , and has lots of features like we use round cube mail and installatron and rv site builder, when looking for your host you should try to get the most that you can for what you are going to pay and settle for no less, also remember to check reviews and to check everything to make sure you are not getting scammed and 24/7 support plus phone support is a good thing too, getting a good reseller account can be sometime difficult but im sure you will find the light....
If you are seriously after a reseller account, you may check HostDime.com, ************* or *********.com, they offer Linux reselling plans with multiple domain hosting, the definite pluses are in-house support and private nameservers offered in their plans.