Harmonic conversion -- Any favorite mixers?

[ezalys]

I'd like to have an auxiliary receiver dedicated to IQ mixer balancing -- that is, I want to discriminate three tones about 50 MHz apart with 30 dB of dynamic range at a frequency of 6 GHz to 12 GHz. To do this cheaply and simply, I'd like to alias down from NxLO + RF. Does anyone have experience doing this? Are there some inexpensive mixers that are better suited for this than others? It seems like designs that do this don't use mixers that are necessarily specified for it, so is it a matter of testing and figuring out which ones work best?

[KE5FX]

What's the application, and do you already have RF ADC(s) in the block diagram?  If you only need 30 dB of dynamic range, you might be surprised at how well some RF ADCs can work in (very!) high Nyquist zones, well beyond their rated specs.

[ezalys]

No ADC. Just looking for a suitable mixer. Ideally better than 30 dB!