I'd like to take a slightly different perspective and challenge you on the need for an MRD.
MRDs are great for known products with well-defined customers on established channels. I know very few startups that meet those criteria. Most of the time, we just have a bunch of hypotheses.
And to take an even further step back, the question any founder seeking capital needs to ask is "what do I need to prove to investors to get funding?" It's not usually that you bought a fancy MRD.
I'm a big proponent of "customer development" and the Lean Startup approach. If you're not familiar with it, the basic concept is that since startups sit in a pool of unknowns, before spending money developing a product and spending like crazy on sales and marketing (read: front-loading risk), founders should spend time developing customers: validating the problem, then the solution, then the business model - all the while building a pool of (hopefully paying) early adopters. At the end, you have customers, revenue, and a whole stack of validated (and invalidated!) hypotheses.
There is very little value in ideas. With billions of people on the planet, you are virtually assured that 10,000 other people have had your idea and a handful are entrepreneurs trying to get it done. The value isn't in the idea; it's in the execution - of the founders. And it can't be staffed out.
So I always tell my clients to prove that you can execute better than them. Hand your potential investors a list of validated hypotheses and a stack of eager customers just begging for you to take their money. And you can do all this at low risk, spending next-to-nothing, while simultaneously giving yourself a better chance at obtaining funding.
Perhaps none of this is new to you and I've just spouted a bunch of things you already know. But I'm still left with the same question I started with: are you sure you need an MRD at this stage?