I worked a lot with malwares since few years, i already developped some crypter/builder/loader for them.
I can basically make your file almost FUD, (NOD32 is hard to bypass, doing this will be really time consuming and would require lot of time).
I cannot give you source that's why i'm making an offer at 100$ and not more. You'll get almost 0 detections. (I think only Nod32 will detect you).
Please if you want to try a test, do no use VirusTotal since it's sending samples to all AV companies making your file detected.
Yours Sincerly.