again, tagging anarchy on an anarchist site is a waste.
as for your question: there are various people who have focused on this question - probably most notably and obviously michael albert and the parecon people (parecon stands for "participatory economy"). and there are a couple anti-state libertarians like shawn wilber who pay a lot of attention to this question in a way that i don't consider hostile to anarchists.
there are also anthropologists who have talked about non-monetary societies (The Gift, is a common reference) in ways that seem appropriate to the kind of world we are talking about.
but in general anarchists don't try to provide blueprints for how society will run after such a major change, partly because we don't think we know, and partly because we think that people will solve their own problems.
at least, that is the tendency on this site.
when we talk about capitalism (and being against it), we're not just talking about how the u.s. operates, but the idea of using money (as a state-controlled exchange form) to reward people for alienated labor (ie that people are forced/encouraged to make things they don't care about for people they don't care about/will never meet). so if your "small or medium enterprises" have anything to do with that model, then no, they would not exist in an anarchist society.