Draw Network in R (control edge thickness plus non-overlapping edges)

Question

I need to draw a network with 5 nodes and 20 directed edges (an edge connecting each 2 nodes) using R, but I need two features to exist:

1. To be able to control the

Answer 1

While not an R answer specifically, I would recommend using Cytoscape to generate the network.

You can automate it using a RCytoscape. http://bioconductor.org/packages/release/bioc/html/RCytoscape.html