While the capability is very common on many alternative phone brands out in the market, not many major manufacturers are coming out with competent phones with it. This is a listing of phones by the more popular brands which can be found in local resellers fashioned in a side by side comparative without any emphasis on any one (click on the image for a larger view):
Most of the data within this sheet come from the very reliable gsmarena portal. Several features that I did not indicate on the image are common to all the phones such as Bluetooth, GPRS, EDGE, and FMRadio. If I were to purchase one I’d probably go with the Champ Duos for now, it is quite similar to my earlier Motorola ROKR E6 with the addition of the WiFi capability, I had bought that one about three years ago at more than twice what the Champ Duos is going for right now.
There is of course special consideration on the interface and how it appeals to the user, this is what sold most Nokia phones in the past. There are a few more options for dual SIM phones I can think of but with the standard 12-key configuration and highly superior battery life. This listing borders on feature phones that share qualities with smartphones. Hope it helps!