i rolled an engy while back for tradeskills and recently lvled him to the 1k spot in most skills, this was just for the purpose of being able to do my own, and help friends with stuff such as making 200 armors imps nanos etc... well mostly what i wanted was the ability to make bronto mantis and that sort of thing, so that was pppe soft. then i didnt want to have to spend a lot of time on an alt so i could hit the 1k point so that was a hit to my pocket.. crackerjack sleeve, spirit devices etc all and all i had to aquire about 120m in cash worth of items and hours and hours of camping for many. my main is an enf and i wouldnt dream of charging to tank a mob, the things that make me where i can tank are the things that make me able to play my char. however you dont need spirit programs mrr's and so on to play an engi that is money people put forward at rediculus prices that one must buy, or as said here camp and try and od agent, soldier etc.. wich even a pretty high lvl engi cannot do.
anyway great thread and while i do most my tradeskills for free, i made an engi to help friends and lowbies mainly so dont really expect much for making 1k skills items, a price guide is nice to see cause those bracers do take a lot of time to make and so do many other items as well as time to camp/farm cash to buy items.
PS. i would charge by how many items and proccesses involved more than skill :P