Does your phone show up as an available device when you sign into the market on a computer? It looks to me like they are concerned about hardware, not software based on this (https://www.google.com/support/androidmarket/bin/answer.py?hl=en&answer=1141080). I have a coworker with a Viewsonic tablet that can't get the market, but I don't see where Google is saying you have to be on a manufacturer authorized ROM... The Droix X is on the list.
I hope you are wrong, and I hope someone can help you get this sorted out. I think I am out of ideas...Yep. It shows up on the list. The reason I mention software is because they specifically asked about it a number of times in the support emails we've been trading back and forth. And if I try to send an app to my phone from the web front end, say, something I'd installed before, it won't let me do it; says it's already installed. They may just be having problems because there's no way to truly remove a device from being authorized on the Market. You can only hide the device from menus. I suspect they're caching device IDs somehow, and eventually — with a lot of ROM flashing, for instance — their backend doesn't know what to do with all of them.
It's just the paranoiac in me that thinks they're dissing open hardware enthusiasts.
I hope you are wrong, and I hope someone can help you get this sorted out. I think I am out of ideas...
I was able to edit build.prop using the root browser in ROM Toolbox. It allowed me to make the change. Once I rebooted I had my customer pulldown text.