Otakus store is good. I got my rgb briefcase from there. Shame they only accept mod work if you're in France.
Yes, I got this stuff and I can attest that it works very well.
Personally, I use it for my PC Engine (the original, the white one) on a Bang & Olufsen TV (MX 4200 for specialists) and the result is simply perfect .. !!
This shop, I have also consolised an MVS slot (MV-1C), modded a SNES (swichless region free) and the work was always very clean.
Bud the bad thing is prices.
It must be recognized that the prices are a bit high, especially compared to the work of some skilled guys who are selling their services on forums ..