The most frustrating thing with these is finding enough Femurs to keep you going. 60-68 is a big gap and with two femurs per synth it'll take hundreds of them to level to 68.
I used to get femurs like crazy in the canyon. I used to make my own meat broth, and farm for the dhamel and rabbit meat. I must have tossed or NPCed hundreds of femurs in that time. They just never seemed profitable enough to bother listing, compared to the seeds and bee chips I also got farming there.
If you want to buy these as a goldsmith to level on, your best option is to find some level 62-ish bonecrafter. These people level on this item, and i found that most have so many bone patas that they npc them to make room for more. For a mere 2k each, most bonecrafters will sell them to you, since that's more then the npc will give them.
To compare: on Ramuh these things sell for 8k at the auction house. That means you pay 4 times more, and will have to wait very long untill someone puts enough of them on AH.