Peter (DK7IH) has been working on HF 6-band SSB transceiver:
Part 1: Project Basic Outline Presentation
Part 2: The Oscillators (VFO, LO and Testtone Osc.)
Part 3: The Microcontroller (ATMega128)
Part 4: Bandswitching Logical Circuits
Part 5: Measuring Transceiver Data
Part 6: The Receiver
Part 7: The Transmitter
Part 8: Transmit/Receive Switch Unit
Part 9: Mechanical construction
Project details on Radiotransmitter site.