Two things
Firstly, this is part of a VERY old debate. At one end there are people who say that any professional PM can manage any project. At the other that only PMs with expertise in say IT delivery can manage say, IT delivery projects. For me, with an IT background in the 19th century, I have since managed projects and programmes in anything from HR to airlines to nano-technology. The key for me is being a professional project or programme manager. As to some of the nitty gritty - thats why you have technical experts. to advise. BUT I also recognise that some individual projects may well benefit from someone with "local" knowledge.
Secondly, a question, why start a consultancy on an area in which expertise is considerably lacking? Focus your business on what services you are able to deliver. There are lots of consultants who focus on PM or business analysis, without the design, development, etc. bits of the life-cycle. Or......simply re-think. But be VERY clear about your value proposition. If you are not, how can your customers know?
Hope this helps.
