I recently did a drop bar build using the WCB-M-062 frame from Workswell (bought through Sobatostore on eBay). It has a longer top tube, steeper head angle, and slightly shorter chainstays than the FM-M009. Either one seems like a good candidate to me. I would expect the FM-M009 to be more stable, while the WCB-M-062 would handle quicker, so it would depend on your preference. Plenty of other Chiner hardtail frames could work as well - I don't think I've seen any that would be too slack or have any other issues for this sort of build.
The biggest thing to keep in mind when building up a MTB frame with drop bars is that the MTB frame will have a significantly longer reach than a similarly sized cross frame (and from what I can tell, longer reach than the Cutthroat frame - my 18.5" WCB-M-062 runs about 50mm longer than a LG Cutthroat), and the drop bars will be extending that reach further than flat/riser bars. You may have to either size down on the frame or use a very short stem to avoid being too stretched out. Personally, I sized down to the 18.5" -062 frame (I'm 6'1" and would normally have chosen the 20") and set it up with a mid-length stem with a bit of rise (nothing too drastic, I believe it was 90mm and +10° with a single 10mm spacer underneath) to set the drops in a similar position to the hoods on my road/cross bikes. I feel much more secure in the drops on singletrack than on the hoods. I'm still in a pretty low and forward position, which feels great on flowy XC trails but can be a little unnerving on steep technical trails. If I were hitting steep descents and rock gardens more often I would probably go for a shorter stem to get my weight further back, or I may have considered a slacker frame.
Another thing you'll have to sort out is shifting compatibility. You've probably looked into this, but if not, make sure you do. I'm not sure about SRAM, but Shimano 11-speed road shifters and MTB derailleurs use different cable pull ratios, so I had to use an adapter in order to have integrated shifters and a clutch derailleur. Bar-end friction shifters seem like a popular choice on most drop bar builds I've seen, but there are adapters out there to match up road shifters with MTB derailleurs, road derailleurs with MTB cassettes, etc, and older systems like 9-speed groups tend to have more cross-compatibility.
Here are some pictures of my build:
https://drive.google.com/drive/folders/0By0tFbxm8cYsaHlsbjhxTVBtNzg?usp=sharing I'm currently running 29x2.25" tires front and rear, and I'm pretty sure I could fit a 2.3" in the frame just fine.
Hope this all helps, and sorry if it was way more info than you needed!
