I bought Pentax 6x7 one year ago. I had neither MF scanner nor dark room that time.
I did'n want to invest 2000 USD in Nikon Coolscan 9000 or more average Epson V750. I decided to try macro method, inspired by:
How to scan films using a digital camera | | Addicted2light Addicted2light
I modified it to K3+macro rings 32mm + M50/4 macro + filter reduction ring + extension tube (part of the waste pipe) + 12w LED panel
The magnification is almost 1:1, so one 6x7 negative consists of 8 APSC photos (matrix of 2 columns x 4 rows), which are merged in SW. K3 focus peaking makes focusing on film corn very accurate. The setup (excluding camera) can be seen here:
Extension tube keeps the lens to film distance constant and helps to keep film flat.
One horizontal merged pair:
PROS:
Low costs. Macro rings and lens are ca 150usd; the rest is almost nothing. I also tested A50/1.4 and was not bad.
Resolution. You decide, what resolution you want. With ca 1:1 macro you get final resolution of ca 11400x9000 px and 300MB file.
Scan quality. The scan quality is comparable to Nikon CoolScan 8000.
EDIT: LED panel. It enables to focus properly. I tried flash as well, but LED panel is better, you need permanent light for focusing
CONS
Less comfort. It does not take a long time to make 8 photos, but merging is an additional work.
This new Pentax replicator would be interesting, if also enables easy and quick multiple macro shooting of the negative. Otherwise it will be just expensive solution with an average scan quality. Probably good for somebody who needs to scan hundreds of negatives and quality is not critical. I also can't imagine, how it will be with focusing since flash is not permanent light.