No it's not, and is done regularly.  I'd assume most making the switch are coming from wires or NYSE regionals -- at least that's the case at my b/d.  Two things I'd consider coming from a wirehouse --

1) Make sure you pick a b/d that can replicate most, if not all, of what you & your clients are used to.  Make a list of everything that's important to you/them (e.g., specific products areas, technology elements, home office support resources, etc.) and verify that the prospective indy b/ds can deliver substantially the same.  There are tons of indy b/d choices, but you'll find many are simply not positioned to have all the things a wirehouse provides.  You/your clients don't want to have any surprises. 

2) When you've done your due diligence & get closer to making a decision get your top choice to have their legal department review & give you guidance re your contractural restrictions, principally non-solicitation and non-compete, if applicable.  They may also refer you to an experienced securities industry attorney.  You want to make sure you handle the transition as clean as possible to minimize any possible legal repercussions (sp?).

That's a very general response to your post.  If you have specific questions, there's several of us here that can probably address them.

Go out and buy “Starting Your Own Practice - The Independence Guide for Professional Service Providers” by Robert Fragasso.  Oh how I wish I’d had that book before I started the process to independence.  I understand that the author is a multi-million dollar independent investment producer.  I didn’t get that from him, although I DID listen in on a conference call that he ran about going independent, and I thought he had some dynamite ideas.  The book is a great blueprint for making the move…good luck…

Fragasso's book would have saved me some $$$ anyone thinking of going indy needs to read the book and follow the advice