[quote] if I'm remembering correctly, the Epson oscillator wasn't cheap and you had to have it programmed for your frequency[/quote]Actually. I think $4.10 is not too bad, and Digikey will program it for free if you specify the frequency when you order. One should be aware that there are versions of the SG-8002 for 3.3 V supplies nowadays, so be sure to order one for 5 V. Also, there is now a version with tighter frequency tolerance, the SGR-8002DB-STB, at the same price.
You don't really have to build up the keyer board. The K-ID2 chip doesn't need it to work in the KØLR circuit. And, the capacitors and inductors are all standard values, so no coils need be wound unless one just enjoys doing that.
Even with the quality and versatility of the U3S, a simple rig like this one can still be useful for beginner or intermediate operators.
John