Hi Bart,
A little bit of insight from RV panel land. To be quite blunt, if you truly want to pay someone to do everything you mentioned, you just as well have them build the entire panel (at least from a financial standpoint). A large majority of the labor for building a panel in professional avionics shops comes from just the sections you mentioned. If you do it yourself you are paying basically what your own salary is worth. If you pay any of us, you're paying our rates. For some people it makes sense to exchange money for time, or have it all done professionally. For others, it makes much more sense to do it on your own.
Overall though, to have a panel cut, painted, labeled as well as mount everything up will be a LONG way towards having the shop do all the rest of the work. Wiring a standard panel is usually not the majority of the labor in a panel...especially with all of the modern interconnects.
All I'd say is look carefully at what you want as an end result and what you want to spend. None of us professional shops are going to do that job in the hundreds of $$'s, it's going to be in the thousands...and like I said, once you get there you won't be far away from getting the entire panel done. Many of my customers (as well as Gary's) are guys who started out on their own and then bring us something to finish - usuallly we start from scratch. If you do it yourself, take the time to do it right. Using Van's standard panel will go a long way to helping you with that as others have mentioned, but there are aftermarket panels that will drop in the same holes as well.
Also, take the words of those who are completely done with a little bit more weight than those who are in the middle of it, or thinking of doing it. Many times the end results aren't quite exactly what the builder envisioned. However, there are a LOT of darned nice panels out there done by builders. Deems has a remarkable airplane overall, so does Bob and Mike so they are proof positive that it can be done, and it can be done well. It's not hard to do, just time consuming. Now, when you get to the physical wiring, that's a whole 'nother issue!
Anyway, I'm sure I didn't add much usefull info in particular, just want to give you my 2 cents as usual.
Cheers,
Stein