I've done three things recently to my 74's rear lights that might be of interest to others.
First I added an LED third brake light unit made by Hella and distributed by danielsternlighting.com. Just go to their site and look for it. There are lots of units out there using standard bulbs, but this is the first stock-looking LED unit I have seen. Best of all is the price...under $50. You can't kluge together a unit at home for that price. Quality merchandise, and Stern is a good outfit to deal with. Very bright light nicely visible. The site rather cleverly tries to talk you into additional bulbs for your car... I bought some that were 20% brighter than stock and was happy I did.
Second I replaced the rear driving/brake bulbs with two LED units from Superbrightleds.com. The bulbs are the 5 watt 1157 RLX5. (yes, in red.) These bulbs do not appear to suffer from the off-axis directionality that many LEDs have long been afflicted with, and they are perhaps 20% brighter than stock. I like the idea that they react to electricity faster than normal bulbs and, at high speeds, give the driver too-closely following you more time to avoid your car. Not cheap at $60, but worth it to me. Obviously you could replace most of the running/taillight bulbs, but these seemed to me the most important ones.
Finally, after gluing the fiberboard to the pot metal rear light housings more than once, to compensate for the broken tabs, and dealing with various resulting shorts and electrical lighting gremlins, I visited my nearby AutoZone for replacement sockets for the size 1156 and 1157 bulbs in the light housings. I have part numbers if anyone cares, but they are pretty much generic. To fit these into the housing you need to drill the stock lamp hole out a tad. I took a die grinder to mine, enlarging the hole slowly and checking the fit of the new socket in hopes of a nice tight press fit. This proved pretty easy to do. Just go slowly and check often. You will need to take a rat tail to opposite sides of the hole to enlarge it a bit to accommodate where the new socket is pushed out to accept the bayonet points on the bulb. Cost per hole, about $4. Not concours, but hardly noticeable even with the plastic lenses off. No more epoxied tabs.
Hope these thoughts will be of use to someone.