How many projects do you consider to be a 'great number'? I ask because I do development in VS with solutions that contain around 300 projects and don't experience anything close to what I would consider 'really sludgy'.
Cool. I see in another response to your post that someone mentions minute load times just to load up the solution file, something which I thankfully have not experienced just yet.
Makes me wonder what's accounting for the varied performance? Probably some combination of project size, plugins, and machine specs, I reckon. If one mans (persons) 10 projects contain 100x the code that my 50 projects contain it would certainly make sense to have longer load times.