Morning All

[baccus61]

I reckon if you can machine a solid with straight sides that just have depth or pockets/protrusions then it would be a 2 1/2D part. Your part has pockets (holes) in the sides as well but that just means you need to turn the part through 90 deg to do the drilling or milling for them. So it is still 2 1/2D.
5 axis machines would pump these things out like there is no tomorrow.
3D parts have curved surfaces or complex surfaces like the parts from for3d on the Russian site. They are all 3D.
The manufacturers would be charging you for set up time and programming the part. The actual part is pretty easy to make but making a jig or setting it up in a vice accurately every time is where the money comes into it. And you are right, they don't make much money on small runs so usually go for the larger runs to maximise profit.
I think with Jazz being so close you will have a viable machine up and running in no time. Certainly a lot quicker that it would have been for me years ago.

I can see a smile developing. he he.!!

Rich.