There was a whole issue of the International Journal of Language & Communication Disorders devoted to SLI recently, mostly looking at whether SLI is an accurate and/or useful term to apply for children with unexplained language disorders.
The Royal College of Speech & Language Therapists have set up an online discussion forum for people interested in SLI - link is here - sli-debate.forums.net/
The two main articles in the IJLCD issue can be accessed here:
1 - Bishop D (2014) “Ten questions about terminology for children with unexplained language problems” - link
2 - Reilly S et al (2014) “Specific language impairment: a convenient label for whom?” - link
and summary of the debate here
Fuck knows when I'll have the mental energy to read this and comment usefully on it, but I bet there's plenty of you who can..... 