Bcd thumbwheel programmable frequency source.

So I finished my 10mhz frequency standard.

I like to build another project, this time a programmable frequency source which can be either clocked by the bbc standard or from a ex mil crystal oven osc I just got on ebay.

If possible I like the thumbwheel readout to equal frequency, ie 000500 = 500hz, I at first thought of 4522's and invert the o/p's of the thumbwheel switches, but thats not gonna work.

Any ideas.

I was thinking maybe theres a 4000 series device suitable, maybe I'll do the job with a pic then.
I have a pll in the freq standard, took a while to get the control loop stable and not too slow.