Anyone here will be willing to make you an N64P. But here's what you need to ask yourself:
1. How much are you willing to spend? This will obviously have a bearing on the overall quality of the portable.
2. Do you want to go with someone reputable here, that has already built one? Maybe you should do some research, and see if there's one specific person who's work stands out to you.
I will build you one. But you need to tell me how much you're looking to spend, OR, what features you want it to have (screen size, battery type/life, built-in rumble/memory... if there's anything specific you want, tell us) and I'll try to give you a quote.
Word of advice, however: Nobody here will build you one for under $100, and that's low-balling it. So don't ask for a $50 portable; it will only get you flamed. I don't know if you know this or not, so I figured I'd tell you just in case.

The "new people" (the term "n00bs" is derogatory) sometimes don't understand the time and money that actually goes into building one of these.