Would adding anything simple to the lamp socket, say different resistors like a low ohm in series or a high ohm in parallel have any effect on the blink rate of the LED blinkers yet still be about as bright? Or is the rate going to stay essentially fixed no matter what?

Those little tealight candle LEDS that flicker extremely randomly are only 3 or 4 cents apiece in bulk, seems like somebody could create a bigger brighter 47 or 44 version that blinks with a little randomness? If real blinkers are vanishing there'd be more incentive to come up with one.

As far as the color I think if you started with a pure white or warm LED and got precise with the physical color filtering in the lens, it would be pretty hard to distinguish it from the color of an incandescent. Seems like currently they are only relying on the actual color of the LED's light (where it seems it's very difficult to exactly recreate the color of a lamp) and the lens is always white or clear. I've used multiple color filter layers on extra bright pure white LEDs to light some faded inserts on a couple of games so the color of the original insert is what I'm aiming for and so they look incandescent-y instead of LED-ish, with good results. On the other hand I recently saw Comet's side by side comparison of a lamp and their 'retro' warm LED and I can't see any difference but haven't tried one.

I'm sure somebody in here could or has come up with a very simple transistor/chip version the size of a quarter that would work for the timer application. Definitely not me though.

Maybe whatever component of the circuit that makes it either a slow or fast blinker could just be changed to use a lot more values in between those two, i.e. if it's just a resistor or capacitor that's determining it. Then just mix 'em up and sell them as 'more randomly timed blinkers'.