Thanks for the kind words. So, you use Conversations for SMSes too? The SIM card in your phone is just a mobile internet thing, you don't actually use it to make calls? I'm curious about your usage. :)
jmp.chat is awesome, that's def. what I use for this. I am deaf, so I don't ever make voice calls, but I use the SMS/MMS features of JMP.chat and am happy.