SonicExplorer
 
Clarification: When I said "I have a number of VST's, such as EQ's, that offer the ability to switch on either Mid or Side but not both" what I really meant was the ability to EQ individually.  

Sorry, I misunderstood. If you're looking for an EQ that can do mid, side, left, right or stereo independently on each band, then FabFilter Pro-Q is just the ticket. I believe DMG Equality can do it, too.
 
To answer the follow-up question, yes and no. Your intuition is correct: applying a HPF to the overall mix to compensate for the brightening of the mix by raising the Sides could in fact reduce the widening effect - somewhat. But it won't completely defeat the effect. What I like to do (when it works) is to put a mirror LPF on the Mid component to compensate, which can also further enhance the widening effect. 

Kamikaze

bitflipper
 
Sorry about the long reply.

I've never seen a post you need to apologies for Bit. Clear concise and reader friendly. By now we could probaby search through all your threads and collate an 'Unofficial BitFlipper's complete guide to Production' int a PDF

I thought it was a fantastic post too. 

That would be embarrassing, because for any collection of my threads to be complete and comprehensive, it would have to include all the times I totally got it wrong.

@bit... Yet, in all the time I've been coming here (not a very active poster...), I've always come to respect your posts (and others as well that I won't mention here for fear of leaving someone out..), and you've always come across as knowledgeable and often offer up why you take that stances/suggestions that you do.
 
Nothing but respect.

Ok guys, I took WideMouth for a quick spin.  Super simple to operate and, if used wisely, is very transparent compared to most other wideners I've tested.  Definitely worth trying out.  You can see how it works in the link in the OP, as well as get the download link there.  It's a simple DLL, no formal "OS install" required. 
 
If anybody else tries it out please post back, I'm curious as to your impression....
 
Sonic