fourfourto's remote start with the factory key fob... works, I'm not sure I'd recommend it, but it's not reprogrammed. The remote start activate is hooked up to the door locks (either lock or unlock), looking for 2 pulses. Any installer would know what you mean if you told them this. I just don't like the fact that anyone can start your truck by hitting the locks twice!
IMO OnStar is just fine, I wouldn't get lojack. If you want more control, you can get something like the viper gps system. That way you can track your truck yourself over the internet or phone, turn it on/off, etc.. and get some vigilante justice if it's stolen.
But of course it's range is limited just like OnStars.