Geeze, Louise. You get it. Good closing argument and summation, Counselor. The bit about trade-offs and concessions strikes a chord.
The low cost DIY requirement is because that is what we do here and it is fun to make stuff. Money is not an object, as I can easily afford a commercially available pickup solution and those suggested over the weekend look very good (although I have no interst in computer modeling apps - why model a D28, if I am playing one? And, if I wanted it to sound like a Gibson or Taylor, I would just buy one of those.) And, I realize I may have to pry open my stainless steel wallet and get something that mounts on the instrument and sounds as it should. It may come to that.
And yet, while the your summation is spot on, perhaps the situation may not be as dire or as absolute as that.
As you suggest, some concession may be necessary. I sometimes contemplate inventing some sort of simple clip that would put a microphone element in or near the sound hole, which is so simple and clever it cannot mar or scuff the finish, while placing the mic element where it is effective.
I imagine a narrow U-shape "thing" that slides over the top around the sound hole and holds a small mic capsule/cartridge. It is lined with very soft felt or (better) a bit of thick, soft flannel cut from a favorite old shirt worn for decades. It does not pinch too hard. It has a very thin Mogami lavalier mic cable loosely leading to a powersupply/matching network - or maybe a small dynamic cartridge cannibalized from a good broadcast headset (like my Audio-Technica BPHS1 on my transceiver) and the cable is provided some sort of strain relieve, perhaps with a clip or other grip "thing" somewhere along the way sorta,kinda like some guys run guitar cables through the strap above the lower bout end pin.) The mounting clip "thing" must be very soft and almost loose, so it cannot scuff the top, yet effectively hold the mic element in place. The mic element might be placed in the sound hole, or or close to it, the way headset microphones sit off the the corner of the mouth to avoid plosives and heavy breathing into the element.
I do not yet know how far an electret element can be from its power supply /matching network and be immune from EMI and RFI, but maybe it would be long enough to give some wiggle room - (did I mention I cannot sit still?) I concede this is tantamount to using the Primo or ATM microphones suggested earlier in the thread - the only significant difference would be how it is powered and matched to the amplifier - but if the cable could be long enough, perhaps that obviates that particular worry, as it would be placed at the amp end of the cable.
The conundrum, therefore, may boil down to picking a sensible mic element, and devising a suitable matching network to the amp, which has both TS instrument and XLR mic inputs, lacking phantom power.
I wonder if anyh of this rambling makes sense. If not, I suppose I will go shopping for the least dangerous, best sounding commercial solution.
In any case, I APPRECIATE the varied solutions proffered and discussed by others in this thread. Some stuff I would not have conjured up on my own. As a local electronics engineer (friend) says, "It's all good." James
