Thinking I'd like to replace the Clutch Perch and the Brake Master Cylinder / Front Brake Perch, along with the Twist Throttle.  Anybody got suggestions for ready-made go to substitutes?

There aren't any. The real problem lies in the indicator circuit because when operated, all three switches provide a momentary signal to earth. As they are on both sides of the handlebars, to change the throttle and switches means modifying the wiring loom to take not only the new switches but to replace the BMW flasher relay with a 'standard' one that takes a continuous signal.

This is the phrase you hate ; it's not difficult if you're happy around wiring and can read a wiring diagram. Both RickG and myself are running non-standard switch-and-throttle setups.

I see you're running an RT but I'm adding this for anyone who's thinking about this and is running a low-bar K: there isn't the room on the handlebars to take a separate clutch bracket/perch and handlebar switch. If you want to go this route you either have to change the handlebars for a pair that are approximately three inches wider or find a pair of pre-1983 (or thereabouts) Honda CB-series handlebar switches as they have the clutch perch/bracket built in and the killswitch operates to break the ignition circuit. Later (CDI) handlebar switches make to kill the ignition. There are also a few odd Suzuki switches with built-in clutch perch/brackets but they are extremely rare.

Now, where's my T-shirt...

[Edit] Clarification: 'there isn't the room on the handlebars to take a separate clutch bracket/perch and handlebar switch'. By this I mean that the clutch cable adjuster almost hits the instrument panel and there isn't enough flexibility in the cable to run around the panel.