You will need a high band QMX+ with 6m to do transverting up to 2m and 70cm.? Failing that 10m had been popular in the past. There are many reasons you won't want yo go lower. When I played with them in the past I have always used the SBL-1 type diode mixers RF fets and MMICs. You will need good quality crystals for the LOs. Lot's of such circuits around. Auto r/f detect T/R switching is the norm. I would start with a 1 or 2W output unit, get it working before boosting the power further up.?
F4WCV