creative_craig - 3:08 pm on Jun 3, 2012 (gmt 0)

Last Christmas I consolidated 4 country sites (country specific domains, hosting, links etc.. and all ranking very well) onto one global domain - my checklist was thorough and felt a little like military procedures. We experienced no drops in rankings or traffic levels at any point and within 6 weeks we were seeing the benefits of the move and traffic has improved month on month since then.

Whilst my situation was different to yours I can't recommend highly enough to plan plan plan!