A lot of analysts have colleagues who can review code. Even if they have no R skills, you could walk them through the program and explain the purpose of each code chunk (btw, this is a great way to organize scripts and write documentation).
But an online community of data analysts who review one another's projects would be useful. You might want to pitch the idea to rOpenSci or the R Consortium
There's not much difference between "general" and "analysis" software, so the review process is similar. And it's possible to bundle a report as a package. Sometimes efficiency isn't a concern, but the other points apply:
- Does it work?
- Does the code follow a style, making it easily read?
- Do the naming and organization help understand what's being done?
- Are there directions for running/using it?
- Do you bundle repeated actions inside functions? Use similar objects (ideally with well-defined structure) to hold similar data?
I would recommend Workflow of Statistical Data Analysis by Oliver Kirchkamp. It's a lengthy guide to writing analysis reports using R. It doesn't explicitly address peer review, but does give opinions on how to code.