Hi Thanos (and all of you good people),
For everyone out there, the best (most reliable, honest, affordable and timeliest) merchant I have found from Alibiba/Aliexpress for doing customised machining is a happy chap called Robin Yang (
robinyang89@gmail.com). His machining is excellent (standard request is +/- 0.03mm accuracy) and he is honest with supply, finishes, timeframes and pricing.
If you need anything done, you'll need to provide him with an IGS file of the part/s you need made. If you're not that way inclined (3D modelling), I can help you out with the required 3D drafting. Just send me a message with a 2D sketch of the part/s and I will do my best to help out.
Hope this helps,
DoctorD