Finished up this iteration of the feeder.

Way smaller overall, and closer to the build surface.

Smaller bearings, no pins minus the feed pin.

Everything prints flat, no supports, with max 4mm bridging required in one spot, 2mm in one other spot, and 0.8mm everywhere else (the tape feed channel on the back).
Supports the tape from the bottom edges with spring tension at the feed window.
Integrated pinch roller for cover tape removal.

Feed area is 20mm high and is currently configured for 12mm deep tapes at widths of 8,12,or 16mm.
Feed lever is 40mm high and vertically actuated.  ~14-18mm of travel will advance it.
The last 2mm of lever travel will disengage the feed pin for tape removal.

Tape feeds and cover tape is removed on release of the feed lever.

Using the hair braiding bands lets me fine tune the amount of cover tape compression for the feed wheel, and advancement.

60mm total height.
140mm long including the servo. 110mm without it.
11.9mm wide for 12mm spacing.

For hardware, it now needs:

• 2 bearings 4x13x5mm.  I forget the number atm..
• 1 M3x5mm bolt
• 1 M3x10mm bolt and nut
• 1 M4x10mm bolt and nut (I may need to cut down a 15mm actually, we will see).
• A short bit of piano wire between .8mm and 1.2mm dia.  A safety pin would work too.
• A handful of silicone hair braiding bands.
• I'm guessing about 25g of relatively stiff filament and a .3mm nozzle to print it with.

Printing now.

EDIT: The tape channel against the bed was too tight from extrusion bleed-over at the start, and is a pain to clean up.

Also, the Lego snap base needs more bending height, as I inadvertently moved from a flexural fit to an interference one.  So it's really hard to get on/off and the tolerances would need to be too tight for mere mortals.  In the process of playing with it I snapped off the tape window too.

I think I may need to have deeper tape channels as well, but then I need to add a horizontal force applied to the edge of the tape to keep it against one side.  Thinking about that made me remember those little stainless hair clips which invert when you push on them.  Wish I had one to play with...  I know they are dirt cheap too..

EDIT 2: Picked up a 10 pack of the hair clips at the dollar store.  They are a little more than 5mm wide for the back part, and already split into two so I can use a single clip to provide spring tension to both the front and back slots with one part.  They are getting added to the design now.