It will be not so "pretty stight forward" as yendori said. Minus 90dBc/Hz at 1kHz will be not an easy task on 2GHz. You will need a low noise PLL chip and good low noise VCO. Something like LMX2347 (integer PLL with -217dBc normalized phase detector noise) or similar may do the job, altough it is crytical due to the very high multiplication ratio (20000) in your case. Use of a fractional PLL chip, which allows the multiplication ratio to be lowered drastically, can be a better choise. National, ADI and Fujitsu are making some sigma-delta fractional chips.