You might have seen these - they're pretty boring, but they work for me. I made scans of the originals (for size mainly) and then printed on Epson Enhanced Matte Paper. (I really like a super flat meter face finish. The definition is not as crisp as other papers, but I'm happy to trade a bit of resolution for an almost totally non-reflective finish on the face.)
After cutting everything out (Olfa compass knife and conventional hobby knives) I coated the prints with Krylon Archival Preservative (rattle can). After two years and a bit the tach red is slightly faded. When I slap in my latest tach face, I think I'll try actually painting in the red with the same hobby paint I used to do the needle tips. (And after having been to the States a few times since making these - I will for sure make the mph inset numbers a little easier to read.....)
I had a lot of fun doing mine too. I made a bunch of different faces, but I ended up settling for the more conventional look of these (except for the little cop car at 160 and the name of an old friend on the bottom of the speedo who was foolish enough to kill himself driving like a knob.) I couldn't resist putting my own name on either. (Hey, at least it's more or less discreet.....)
I use stainless aircraft safety wire to "sew" my rings on. I also add just the tiniest dab of JB weld to hide the wire. If you place the cut in the right spot when reassembling the 400/4 gauges, you pretty much can't see it anyways. My biggest problem was actually with the voltmeter ring - the housing is much smaller than the (already small) tach and speedo - so any joining work is proportionally larger.
I like this system of ring reassembly because it's really easy to get back inside the meters (for lubing and to swap out the faces). It might not work as well for those bikes where the meter placement isn't so advantageous to hiding the join as is the 400F.