I was in the same boat as you! I finally settled on the PM25MV from Quality Machine Tools. (PM-MV Milling Machines) This is basically a BF20/G0704 or any other clone of the original BF20. The conversions are the same cost as any conversion for the X3 as well as the electronics. From my research the BF20's seem to be a tweakers heaven. I like to change and modify and tweak pretty much everything I own. Nothing is good enough OEM for me, and the vast amount of knowledge and documented mods to every variation of the BF20 seems to be only limited by a persons imagination. There are some small differnces between manufacturers like motor size and max drill capacity, but the basics are the same. Hope I helped and I look forward to your updates and hopefully a build log.
BTW, quality machine tools is supposed to be getting a shipment of the PM25MV's by the end of this month. Once QA is done then they will ship to customers some time mid June. This is the shipment that my mill is supposed to be on... Fingers Crossed!