I like working with informed, self motivated and legitimate investors. But, that's the same as any other type of buyer. A very small percentage of the people I field calls from actually end up buying anything. I wish there was a science to vetting buyers, but only flags that can be used as cues when someones wasting their time.
If I were buying something out of state and needed to find an agent, here's what I'd look for. I'd find the most productive office I could, then pick an agent from it that had 18-24 months experience. Explain to them my strategy, what I'm looking for and how often I want them to check in if no matches are coming up. I'd know that agent was around "hitters" and was seeing a lot of properties before they hit the MLS, but still needed to build their client list that my needs are a high priority and I come to mind first.
Just keep in mind that the idea of lowballing isn't very common anymore, every home has a value and the amount of information available has changed the industry a lot. You're not looking for a steal, you're looking for something that fits your parameters and most listing agents aren't going to let their clients get hammered. I've had a lot of lowball offers come in to my clients, they're usually upset and less likely to negotiate, I also tell them that if they would take something that low, I'd like a chance to speak with some of my investors and I'll cut my 6% commission a little in appreciation.